| Message ID | 20201128213527.2669807-5-christian.brauner@ubuntu.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | idmapped mounts | expand |
Lots of crazy long lines in the patch. Remember that you should only go past 80 lines if it clearly improves readability, and I don't think it does anywhere in here. > index a7cd0f64faa4..a5a6c470dc07 100644 > --- a/fs/internal.h > +++ b/fs/internal.h > @@ -82,6 +82,14 @@ int may_linkat(struct path *link); > /* > * namespace.c > */ > +struct mount_kattr { > + unsigned int attr_set; > + unsigned int attr_clr; > + unsigned int propagation; > + unsigned int lookup_flags; > + bool recurse; > +}; Even with the whole series applied this structure is only used in namespace.c, so it might be worth moving there. > +static inline int mnt_hold_writers(struct mount *mnt) > { > - int ret = 0; > - > mnt->mnt.mnt_flags |= MNT_WRITE_HOLD; > /* > * After storing MNT_WRITE_HOLD, we'll read the counters. This store > @@ -497,15 +495,29 @@ static int mnt_make_readonly(struct mount *mnt) > * we're counting up here. > */ > if (mnt_get_writers(mnt) > 0) > - ret = -EBUSY; > - else > - mnt->mnt.mnt_flags |= MNT_READONLY; > + return -EBUSY; > + > + return 0; > +} > + > +static inline void mnt_unhold_writers(struct mount *mnt) > +{ > /* > * MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers > * that become unheld will see MNT_READONLY. > */ > smp_wmb(); > mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; > +} > + > +static int mnt_make_readonly(struct mount *mnt) > +{ > + int ret; > + > + ret = mnt_hold_writers(mnt); > + if (!ret) > + mnt->mnt.mnt_flags |= MNT_READONLY; > + mnt_unhold_writers(mnt); > return ret; > } > > @@ -3438,6 +3450,33 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, > return ret; > } This refactoring seems worth a little prep patch. > > +static int build_attr_flags(unsigned int attr_flags, unsigned int *flags) > +{ > + unsigned int aflags = 0; > + > + if (attr_flags & ~(MOUNT_ATTR_RDONLY | > + MOUNT_ATTR_NOSUID | > + MOUNT_ATTR_NODEV | > + MOUNT_ATTR_NOEXEC | > + MOUNT_ATTR__ATIME | > + MOUNT_ATTR_NODIRATIME)) > + return -EINVAL; > + > + if (attr_flags & MOUNT_ATTR_RDONLY) > + aflags |= MNT_READONLY; > + if (attr_flags & MOUNT_ATTR_NOSUID) > + aflags |= MNT_NOSUID; > + if (attr_flags & MOUNT_ATTR_NODEV) > + aflags |= MNT_NODEV; > + if (attr_flags & MOUNT_ATTR_NOEXEC) > + aflags |= MNT_NOEXEC; > + if (attr_flags & MOUNT_ATTR_NODIRATIME) > + aflags |= MNT_NODIRATIME; > + > + *flags = aflags; > + return 0; > +} Same for adding this helper. > + *kattr = (struct mount_kattr){ Missing whitespace before the {. > + switch (attr->propagation) { > + case MAKE_PROPAGATION_UNCHANGED: > + kattr->propagation = 0; > + break; > + case MAKE_PROPAGATION_UNBINDABLE: > + kattr->propagation = MS_UNBINDABLE; > + break; > + case MAKE_PROPAGATION_PRIVATE: > + kattr->propagation = MS_PRIVATE; > + break; > + case MAKE_PROPAGATION_DEPENDENT: > + kattr->propagation = MS_SLAVE; > + break; > + case MAKE_PROPAGATION_SHARED: > + kattr->propagation = MS_SHARED; > + break; > + default: Any reason to not just reuse the MS_* flags in the new API? Yes, your new names are more descriptive, but having different names for the same thing is also rather confusing. > + if (upper_32_bits(attr->attr_set)) > + return -EINVAL; > + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) > + return -EINVAL; > + > + if (upper_32_bits(attr->attr_clr)) > + return -EINVAL; > + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) > + return -EINVAL; What is so magic about the upper and lower 32 bits? > + return -EINVAL; > + else if ((attr->attr_clr & MOUNT_ATTR__ATIME) && > + ((attr->attr_clr & MOUNT_ATTR__ATIME) != MOUNT_ATTR__ATIME)) > + return -EINVAL; No need for the else here. That being said I'd reword the thing to be a little more obvious: if (attr->attr_clr & MOUNT_ATTR__ATIME) { if ((attr->attr_clr & MOUNT_ATTR__ATIME) != MOUNT_ATTR__ATIME) return -EINVAL; ... code doing the update of the atime flags here } else { if (attr->attr_set & MOUNT_ATTR__ATIME) return -EINVAL; } > +/* Change propagation through mount_setattr(). */ > +enum propagation_type { > + MAKE_PROPAGATION_UNCHANGED = 0, /* Don't change mount propagation (default). */ > + MAKE_PROPAGATION_UNBINDABLE = 1, /* Make unbindable. */ > + MAKE_PROPAGATION_PRIVATE = 2, /* Do not receive or send mount events. */ > + MAKE_PROPAGATION_DEPENDENT = 3, /* Only receive mount events. */ > + MAKE_PROPAGATION_SHARED = 4, /* Send and receive mount events. */ > +}; FYI, in uapis using defines instead of enums is usually the better choice, as that allows userspace to probe for later added defines. But if we use MS_* here that would be void anyway. > +/* List of all mount_attr versions. */ > +#define MOUNT_ATTR_SIZE_VER0 24 /* sizeof first published struct */ > +#define MOUNT_ATTR_SIZE_LATEST MOUNT_ATTR_SIZE_VER0 The _LATEST things is pretty dangerous as there basically is no safe and correct way for userspace to use it.
On Tue, Dec 01, 2020 at 11:49:07AM +0100, Christoph Hellwig wrote: Sorry for not responding to this yesterday. I missed most of your mails because they have been filtered into a dedicated folder (as they should be) and I would've looked into that folder but somehow gmail let ~3 mails of you into my general inbox and so I didn't bother... > Lots of crazy long lines in the patch. Remember that you should only > go past 80 lines if it clearly improves readability, and I don't > think it does anywhere in here. Weird, I did reformat the patch to the 80 char limit and I have dual display in vim, meaning I have a visible line at 80 chars and 100 chars whenever I edit a file. I'll go through it again, thanks! > > > index a7cd0f64faa4..a5a6c470dc07 100644 > > --- a/fs/internal.h > > +++ b/fs/internal.h > > @@ -82,6 +82,14 @@ int may_linkat(struct path *link); > > /* > > * namespace.c > > */ > > +struct mount_kattr { > > + unsigned int attr_set; > > + unsigned int attr_clr; > > + unsigned int propagation; > > + unsigned int lookup_flags; > > + bool recurse; > > +}; > > Even with the whole series applied this structure is only used in > namespace.c, so it might be worth moving there. Good point. Will do. > > > +static inline int mnt_hold_writers(struct mount *mnt) > > { > > - int ret = 0; > > - > > mnt->mnt.mnt_flags |= MNT_WRITE_HOLD; > > /* > > * After storing MNT_WRITE_HOLD, we'll read the counters. This store > > @@ -497,15 +495,29 @@ static int mnt_make_readonly(struct mount *mnt) > > * we're counting up here. > > */ > > if (mnt_get_writers(mnt) > 0) > > - ret = -EBUSY; > > - else > > - mnt->mnt.mnt_flags |= MNT_READONLY; > > + return -EBUSY; > > + > > + return 0; > > +} > > + > > +static inline void mnt_unhold_writers(struct mount *mnt) > > +{ > > /* > > * MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers > > * that become unheld will see MNT_READONLY. > > */ > > smp_wmb(); > > mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; > > +} > > + > > +static int mnt_make_readonly(struct mount *mnt) > > +{ > > + int ret; > > + > > + ret = mnt_hold_writers(mnt); > > + if (!ret) > > + mnt->mnt.mnt_flags |= MNT_READONLY; > > + mnt_unhold_writers(mnt); > > return ret; > > } > > > > @@ -3438,6 +3450,33 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, > > return ret; > > } > > This refactoring seems worth a little prep patch. Will split into separate patch. > > > > > +static int build_attr_flags(unsigned int attr_flags, unsigned int *flags) > > +{ > > + unsigned int aflags = 0; > > + > > + if (attr_flags & ~(MOUNT_ATTR_RDONLY | > > + MOUNT_ATTR_NOSUID | > > + MOUNT_ATTR_NODEV | > > + MOUNT_ATTR_NOEXEC | > > + MOUNT_ATTR__ATIME | > > + MOUNT_ATTR_NODIRATIME)) > > + return -EINVAL; > > + > > + if (attr_flags & MOUNT_ATTR_RDONLY) > > + aflags |= MNT_READONLY; > > + if (attr_flags & MOUNT_ATTR_NOSUID) > > + aflags |= MNT_NOSUID; > > + if (attr_flags & MOUNT_ATTR_NODEV) > > + aflags |= MNT_NODEV; > > + if (attr_flags & MOUNT_ATTR_NOEXEC) > > + aflags |= MNT_NOEXEC; > > + if (attr_flags & MOUNT_ATTR_NODIRATIME) > > + aflags |= MNT_NODIRATIME; > > + > > + *flags = aflags; > > + return 0; > > +} > > Same for adding this helper. Will do. > > > + *kattr = (struct mount_kattr){ > > Missing whitespace before the {. Good spot, thank you! > > > + switch (attr->propagation) { > > + case MAKE_PROPAGATION_UNCHANGED: > > + kattr->propagation = 0; > > + break; > > + case MAKE_PROPAGATION_UNBINDABLE: > > + kattr->propagation = MS_UNBINDABLE; > > + break; > > + case MAKE_PROPAGATION_PRIVATE: > > + kattr->propagation = MS_PRIVATE; > > + break; > > + case MAKE_PROPAGATION_DEPENDENT: > > + kattr->propagation = MS_SLAVE; > > + break; > > + case MAKE_PROPAGATION_SHARED: > > + kattr->propagation = MS_SHARED; > > + break; > > + default: > > Any reason to not just reuse the MS_* flags in the new API? Yes, your > new names are more descriptive, but having different names for the same > thing is also rather confusing. I'm not really married to this so I don't see a reason why not. > > > + if (upper_32_bits(attr->attr_set)) > > + return -EINVAL; > > + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) > > + return -EINVAL; > > + > > + if (upper_32_bits(attr->attr_clr)) > > + return -EINVAL; > > + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) > > + return -EINVAL; > > What is so magic about the upper and lower 32 bits? Nothing apart from the fact that they arent't currently valid. I can think about reworking these lines. Or do you already have a preferred way of doing this in mind? > > > + return -EINVAL; > > + else if ((attr->attr_clr & MOUNT_ATTR__ATIME) && > > + ((attr->attr_clr & MOUNT_ATTR__ATIME) != MOUNT_ATTR__ATIME)) > > + return -EINVAL; > > No need for the else here. Thanks! > > That being said I'd reword the thing to be a little more obvious: > > if (attr->attr_clr & MOUNT_ATTR__ATIME) { > if ((attr->attr_clr & MOUNT_ATTR__ATIME) != MOUNT_ATTR__ATIME) > return -EINVAL; > > ... code doing the update of the atime flags here > } else { > if (attr->attr_set & MOUNT_ATTR__ATIME) > return -EINVAL; > } Will do. > > > > +/* Change propagation through mount_setattr(). */ > > +enum propagation_type { > > + MAKE_PROPAGATION_UNCHANGED = 0, /* Don't change mount propagation (default). */ > > + MAKE_PROPAGATION_UNBINDABLE = 1, /* Make unbindable. */ > > + MAKE_PROPAGATION_PRIVATE = 2, /* Do not receive or send mount events. */ > > + MAKE_PROPAGATION_DEPENDENT = 3, /* Only receive mount events. */ > > + MAKE_PROPAGATION_SHARED = 4, /* Send and receive mount events. */ > > +}; > > FYI, in uapis using defines instead of enums is usually the better > choice, as that allows userspace to probe for later added defines. > > But if we use MS_* here that would be void anyway. Indeed. > > > +/* List of all mount_attr versions. */ > > +#define MOUNT_ATTR_SIZE_VER0 24 /* sizeof first published struct */ > > +#define MOUNT_ATTR_SIZE_LATEST MOUNT_ATTR_SIZE_VER0 > > The _LATEST things is pretty dangerous as there basically is no safe > and correct way for userspace to use it. Ok, I'll remove the _LATEST. Thanks for the review (and sorry again for missing your mails)! Christian
On Wed, Dec 02, 2020 at 10:42:18AM +0100, Christian Brauner wrote: > > > + if (upper_32_bits(attr->attr_set)) > > > + return -EINVAL; > > > + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) > > > + return -EINVAL; > > > + > > > + if (upper_32_bits(attr->attr_clr)) > > > + return -EINVAL; > > > + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) > > > + return -EINVAL; > > > > What is so magic about the upper and lower 32 bits? > > Nothing apart from the fact that they arent't currently valid. I can > think about reworking these lines. Or do you already have a preferred > way of doing this in mind? Just turn the attr_flags argument to build_attr_flags into a u64 and the first sanity check there will catch all invalid flags, no matter where they are places. That should also generate more efficient code.
On Wed, Dec 02, 2020 at 10:47:51AM +0100, Christoph Hellwig wrote: > On Wed, Dec 02, 2020 at 10:42:18AM +0100, Christian Brauner wrote: > > > > + if (upper_32_bits(attr->attr_set)) > > > > + return -EINVAL; > > > > + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) > > > > + return -EINVAL; > > > > + > > > > + if (upper_32_bits(attr->attr_clr)) > > > > + return -EINVAL; > > > > + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) > > > > + return -EINVAL; > > > > > > What is so magic about the upper and lower 32 bits? > > > > Nothing apart from the fact that they arent't currently valid. I can > > think about reworking these lines. Or do you already have a preferred > > way of doing this in mind? > > Just turn the attr_flags argument to build_attr_flags into a u64 and > the first sanity check there will catch all invalid flags, no matter > where they are places. That should also generate more efficient code. And while we're at it: the check for valid flags in the current code is a little weird, given that build_attr_flags checks for them, and but sys_fsmount also has its own slightly narrower checks. I think it might make sense to split the validity check out of build_attr_flags. E.g. something like: static unsigned int attr_flags_to_mnt_flags(u64 attr_flags) { unsigned int mnt_flags = 0; if (attr_flags & MOUNT_ATTR_RDONLY) mnt_flags |= MNT_READONLY; if (attr_flags & MOUNT_ATTR_NOSUID) mnt_flags |= MNT_NOSUID; if (attr_flags & MOUNT_ATTR_NODEV) mnt_flags |= MNT_NODEV; if (attr_flags & MOUNT_ATTR_NOEXEC) mnt_flags |= MNT_NOEXEC; if (attr_flags & MOUNT_ATTR_NODIRATIME) mnt_flags |= MNT_NODIRATIME; return mnt_flags; } #define MOUNT_SETATTR_VALID_FLAGS \ (MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOSUID | MOUNT_ATTR_NODEV | \ MOUNT_ATTR_NOEXEC | MOUNT_ATTR__ATIME | MOUNT_ATTR_NODIRATIME | \ MOUNT_ATTR_IDMAP) static int build_mount_kattr(const struct mount_attr *attr, size_t usize, struct mount_kattr *kattr, unsigned int flags) { ... if ((attr->attr_set | attr->attr_clr) & ~MOUNT_SETATTR_VALID_FLAGS) return -EINVAL; kattr->attr_set = attr_flags_to_mnt_flags(attr->attr_set); kattr->attr_clr = attr_flags_to_mnt_flags(attr->attr_clr); ... }
On Wed, Dec 02, 2020 at 10:55:47AM +0100, Christoph Hellwig wrote: > On Wed, Dec 02, 2020 at 10:47:51AM +0100, Christoph Hellwig wrote: > > On Wed, Dec 02, 2020 at 10:42:18AM +0100, Christian Brauner wrote: > > > > > + if (upper_32_bits(attr->attr_set)) > > > > > + return -EINVAL; > > > > > + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) > > > > > + return -EINVAL; > > > > > + > > > > > + if (upper_32_bits(attr->attr_clr)) > > > > > + return -EINVAL; > > > > > + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) > > > > > + return -EINVAL; > > > > > > > > What is so magic about the upper and lower 32 bits? > > > > > > Nothing apart from the fact that they arent't currently valid. I can > > > think about reworking these lines. Or do you already have a preferred > > > way of doing this in mind? > > > > Just turn the attr_flags argument to build_attr_flags into a u64 and > > the first sanity check there will catch all invalid flags, no matter > > where they are places. That should also generate more efficient code. > > And while we're at it: the check for valid flags in the current > code is a little weird, given that build_attr_flags checks for > them, and but sys_fsmount also has its own slightly narrower checks. > > I think it might make sense to split the validity check out of > build_attr_flags. E.g. something like: Sounds good! If we make this a preparatory patch do you want to be recorded in the author field? > > static unsigned int attr_flags_to_mnt_flags(u64 attr_flags) > { > unsigned int mnt_flags = 0; > > if (attr_flags & MOUNT_ATTR_RDONLY) > mnt_flags |= MNT_READONLY; > if (attr_flags & MOUNT_ATTR_NOSUID) > mnt_flags |= MNT_NOSUID; > if (attr_flags & MOUNT_ATTR_NODEV) > mnt_flags |= MNT_NODEV; > if (attr_flags & MOUNT_ATTR_NOEXEC) > mnt_flags |= MNT_NOEXEC; > if (attr_flags & MOUNT_ATTR_NODIRATIME) > mnt_flags |= MNT_NODIRATIME; > > return mnt_flags; > } > > #define MOUNT_SETATTR_VALID_FLAGS \ > (MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOSUID | MOUNT_ATTR_NODEV | \ > MOUNT_ATTR_NOEXEC | MOUNT_ATTR__ATIME | MOUNT_ATTR_NODIRATIME | \ > MOUNT_ATTR_IDMAP) > > static int build_mount_kattr(const struct mount_attr *attr, size_t usize, > struct mount_kattr *kattr, unsigned int flags) > { > ... > > if ((attr->attr_set | attr->attr_clr) & ~MOUNT_SETATTR_VALID_FLAGS) > return -EINVAL; > kattr->attr_set = attr_flags_to_mnt_flags(attr->attr_set); > kattr->attr_clr = attr_flags_to_mnt_flags(attr->attr_clr); > ... > }
On Wed, Dec 02, 2020 at 10:57:45AM +0100, Christian Brauner wrote: > Sounds good! > If we make this a preparatory patch do you want to be recorded in the > author field? No need to record me in any way. This was just whiteboard coding.
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl index ee7b01bb7346..24d8709624b8 100644 --- a/arch/alpha/kernel/syscalls/syscall.tbl +++ b/arch/alpha/kernel/syscalls/syscall.tbl @@ -480,3 +480,4 @@ 548 common pidfd_getfd sys_pidfd_getfd 549 common faccessat2 sys_faccessat2 550 common process_madvise sys_process_madvise +551 common mount_setattr sys_mount_setattr diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index d056a548358e..e3785513d445 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -454,3 +454,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h index 107f08e03b9f..78af754e070a 100644 --- a/arch/arm64/include/asm/unistd32.h +++ b/arch/arm64/include/asm/unistd32.h @@ -889,6 +889,8 @@ __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd) __SYSCALL(__NR_faccessat2, sys_faccessat2) #define __NR_process_madvise 440 __SYSCALL(__NR_process_madvise, sys_process_madvise) +#define __NR_mount_setattr 441 +__SYSCALL(__NR_mount_setattr, sys_mount_setattr) /* * Please add new compat syscalls above this comment and update diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl index b96ed8b8a508..f7d4b1f55be0 100644 --- a/arch/ia64/kernel/syscalls/syscall.tbl +++ b/arch/ia64/kernel/syscalls/syscall.tbl @@ -361,3 +361,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl index 625fb6d32842..e96e9c6a6ffa 100644 --- a/arch/m68k/kernel/syscalls/syscall.tbl +++ b/arch/m68k/kernel/syscalls/syscall.tbl @@ -440,3 +440,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl index aae729c95cf9..6538f075a18e 100644 --- a/arch/microblaze/kernel/syscalls/syscall.tbl +++ b/arch/microblaze/kernel/syscalls/syscall.tbl @@ -446,3 +446,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index 32817c954435..64d129db1aa7 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -379,3 +379,4 @@ 438 n32 pidfd_getfd sys_pidfd_getfd 439 n32 faccessat2 sys_faccessat2 440 n32 process_madvise sys_process_madvise +441 n32 mount_setattr sys_mount_setattr diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl index 9e4ea3c31b1c..94b24e6b2608 100644 --- a/arch/mips/kernel/syscalls/syscall_n64.tbl +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl @@ -355,3 +355,4 @@ 438 n64 pidfd_getfd sys_pidfd_getfd 439 n64 faccessat2 sys_faccessat2 440 n64 process_madvise sys_process_madvise +441 n64 mount_setattr sys_mount_setattr diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index 29f5f28cf5ce..eae522306767 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -428,3 +428,4 @@ 438 o32 pidfd_getfd sys_pidfd_getfd 439 o32 faccessat2 sys_faccessat2 440 o32 process_madvise sys_process_madvise +441 o32 mount_setattr sys_mount_setattr diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl index f375ea528e59..c7e25f1d219f 100644 --- a/arch/parisc/kernel/syscalls/syscall.tbl +++ b/arch/parisc/kernel/syscalls/syscall.tbl @@ -438,3 +438,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl index 1275daec7fec..0b309ef64e91 100644 --- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl @@ -530,3 +530,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl index 28c168000483..0b30398fee42 100644 --- a/arch/s390/kernel/syscalls/syscall.tbl +++ b/arch/s390/kernel/syscalls/syscall.tbl @@ -443,3 +443,4 @@ 438 common pidfd_getfd sys_pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr sys_mount_setattr diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl index 783738448ff5..8e4949c5b740 100644 --- a/arch/sh/kernel/syscalls/syscall.tbl +++ b/arch/sh/kernel/syscalls/syscall.tbl @@ -443,3 +443,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl index 78160260991b..409f21a650b8 100644 --- a/arch/sparc/kernel/syscalls/syscall.tbl +++ b/arch/sparc/kernel/syscalls/syscall.tbl @@ -486,3 +486,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 0d0667a9fbd7..2a694420f6cd 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -445,3 +445,4 @@ 438 i386 pidfd_getfd sys_pidfd_getfd 439 i386 faccessat2 sys_faccessat2 440 i386 process_madvise sys_process_madvise +441 i386 mount_setattr sys_mount_setattr diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 379819244b91..4d594d0246c1 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -362,6 +362,7 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr # # Due to a historical design error, certain syscalls are numbered differently diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl index b070f272995d..a650dc05593d 100644 --- a/arch/xtensa/kernel/syscalls/syscall.tbl +++ b/arch/xtensa/kernel/syscalls/syscall.tbl @@ -411,3 +411,4 @@ 438 common pidfd_getfd sys_pidfd_getfd 439 common faccessat2 sys_faccessat2 440 common process_madvise sys_process_madvise +441 common mount_setattr sys_mount_setattr diff --git a/fs/internal.h b/fs/internal.h index a7cd0f64faa4..a5a6c470dc07 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -82,6 +82,14 @@ int may_linkat(struct path *link); /* * namespace.c */ +struct mount_kattr { + unsigned int attr_set; + unsigned int attr_clr; + unsigned int propagation; + unsigned int lookup_flags; + bool recurse; +}; + extern struct vfsmount *lookup_mnt(const struct path *); extern int finish_automount(struct vfsmount *, struct path *); diff --git a/fs/namespace.c b/fs/namespace.c index 8497d149ecaa..f9ea31b7eb7f 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -469,10 +469,8 @@ void mnt_drop_write_file(struct file *file) } EXPORT_SYMBOL(mnt_drop_write_file); -static int mnt_make_readonly(struct mount *mnt) +static inline int mnt_hold_writers(struct mount *mnt) { - int ret = 0; - mnt->mnt.mnt_flags |= MNT_WRITE_HOLD; /* * After storing MNT_WRITE_HOLD, we'll read the counters. This store @@ -497,15 +495,29 @@ static int mnt_make_readonly(struct mount *mnt) * we're counting up here. */ if (mnt_get_writers(mnt) > 0) - ret = -EBUSY; - else - mnt->mnt.mnt_flags |= MNT_READONLY; + return -EBUSY; + + return 0; +} + +static inline void mnt_unhold_writers(struct mount *mnt) +{ /* * MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers * that become unheld will see MNT_READONLY. */ smp_wmb(); mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; +} + +static int mnt_make_readonly(struct mount *mnt) +{ + int ret; + + ret = mnt_hold_writers(mnt); + if (!ret) + mnt->mnt.mnt_flags |= MNT_READONLY; + mnt_unhold_writers(mnt); return ret; } @@ -3438,6 +3450,33 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, return ret; } +static int build_attr_flags(unsigned int attr_flags, unsigned int *flags) +{ + unsigned int aflags = 0; + + if (attr_flags & ~(MOUNT_ATTR_RDONLY | + MOUNT_ATTR_NOSUID | + MOUNT_ATTR_NODEV | + MOUNT_ATTR_NOEXEC | + MOUNT_ATTR__ATIME | + MOUNT_ATTR_NODIRATIME)) + return -EINVAL; + + if (attr_flags & MOUNT_ATTR_RDONLY) + aflags |= MNT_READONLY; + if (attr_flags & MOUNT_ATTR_NOSUID) + aflags |= MNT_NOSUID; + if (attr_flags & MOUNT_ATTR_NODEV) + aflags |= MNT_NODEV; + if (attr_flags & MOUNT_ATTR_NOEXEC) + aflags |= MNT_NOEXEC; + if (attr_flags & MOUNT_ATTR_NODIRATIME) + aflags |= MNT_NODIRATIME; + + *flags = aflags; + return 0; +} + /* * Create a kernel mount representation for a new, prepared superblock * (specified by fs_fd) and attach to an open_tree-like file descriptor. @@ -3460,24 +3499,9 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, if ((flags & ~(FSMOUNT_CLOEXEC)) != 0) return -EINVAL; - if (attr_flags & ~(MOUNT_ATTR_RDONLY | - MOUNT_ATTR_NOSUID | - MOUNT_ATTR_NODEV | - MOUNT_ATTR_NOEXEC | - MOUNT_ATTR__ATIME | - MOUNT_ATTR_NODIRATIME)) - return -EINVAL; - - if (attr_flags & MOUNT_ATTR_RDONLY) - mnt_flags |= MNT_READONLY; - if (attr_flags & MOUNT_ATTR_NOSUID) - mnt_flags |= MNT_NOSUID; - if (attr_flags & MOUNT_ATTR_NODEV) - mnt_flags |= MNT_NODEV; - if (attr_flags & MOUNT_ATTR_NOEXEC) - mnt_flags |= MNT_NOEXEC; - if (attr_flags & MOUNT_ATTR_NODIRATIME) - mnt_flags |= MNT_NODIRATIME; + ret = build_attr_flags(attr_flags, &mnt_flags); + if (ret) + return ret; switch (attr_flags & MOUNT_ATTR__ATIME) { case MOUNT_ATTR_STRICTATIME: @@ -3785,6 +3809,261 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, return error; } +static unsigned int recalc_flags(struct mount_kattr *kattr, struct mount *mnt) +{ + unsigned int flags = mnt->mnt.mnt_flags; + + /* flags to clear */ + flags &= ~kattr->attr_clr; + /* flags to raise */ + flags |= kattr->attr_set; + + return flags; +} + +static struct mount *mount_setattr_prepare(struct mount_kattr *kattr, + struct mount *mnt, int *err) +{ + struct mount *m = mnt, *last = NULL; + + if (!is_mounted(&m->mnt)) { + *err = -EINVAL; + goto out; + } + + if (!(mnt_has_parent(m) ? check_mnt(m) : is_anon_ns(m->mnt_ns))) { + *err = -EINVAL; + goto out; + } + + do { + unsigned int flags; + + flags = recalc_flags(kattr, m); + if (!can_change_locked_flags(m, flags)) { + *err = -EPERM; + goto out; + } + + last = m; + + if ((kattr->attr_set & MNT_READONLY) && + !(m->mnt.mnt_flags & MNT_READONLY)) { + *err = mnt_hold_writers(m); + if (*err) + goto out; + } + } while (kattr->recurse && (m = next_mnt(m, mnt))); + +out: + return last; +} + +static void mount_setattr_commit(struct mount_kattr *kattr, struct mount *mnt, + struct mount *last, int err) +{ + struct mount *m = mnt; + + do { + if (!err) { + unsigned int flags; + + flags = recalc_flags(kattr, m); + WRITE_ONCE(m->mnt.mnt_flags, flags); + } + + /* + * We either set MNT_READONLY above so make it visible + * before ~MNT_WRITE_HOLD or we failed to recursively + * apply mount options. + */ + if ((kattr->attr_set & MNT_READONLY) && + (m->mnt.mnt_flags & MNT_WRITE_HOLD)) + mnt_unhold_writers(m); + + if (!err && kattr->propagation) + change_mnt_propagation(m, kattr->propagation); + + /* + * On failure, only cleanup until we found the first mount we + * failed to handle. + */ + if (err && m == last) + break; + } while (kattr->recurse && (m = next_mnt(m, mnt))); + + if (!err) + touch_mnt_namespace(mnt->mnt_ns); +} + +static int do_mount_setattr(struct path *path, struct mount_kattr *kattr) +{ + struct mount *mnt = real_mount(path->mnt), *last = NULL; + int err = 0; + + if (path->dentry != mnt->mnt.mnt_root) + return -EINVAL; + + if (kattr->propagation) { + /* + * Only take namespace_lock() if we're actually changing + * propagation. + */ + namespace_lock(); + if (kattr->propagation == MS_SHARED) { + err = invent_group_ids(mnt, kattr->recurse); + if (err) { + namespace_unlock(); + return err; + } + } + } + + lock_mount_hash(); + + /* + * Get the mount tree in a shape where we can change mount properties + * without failure. + */ + last = mount_setattr_prepare(kattr, mnt, &err); + if (last) /* Commit all changes or revert to the old state. */ + mount_setattr_commit(kattr, mnt, last, err); + + unlock_mount_hash(); + + if (kattr->propagation) { + namespace_unlock(); + if (err) + cleanup_group_ids(mnt, NULL); + } + + return err; +} + +static int build_mount_kattr(const struct mount_attr *attr, + struct mount_kattr *kattr, unsigned int flags) +{ + unsigned int lookup_flags = LOOKUP_AUTOMOUNT | LOOKUP_FOLLOW; + + if (flags & AT_NO_AUTOMOUNT) + lookup_flags &= ~LOOKUP_AUTOMOUNT; + if (flags & AT_SYMLINK_NOFOLLOW) + lookup_flags &= ~LOOKUP_FOLLOW; + if (flags & AT_EMPTY_PATH) + lookup_flags |= LOOKUP_EMPTY; + + *kattr = (struct mount_kattr){ + .lookup_flags = lookup_flags, + .recurse = !!(flags & AT_RECURSIVE), + }; + + switch (attr->propagation) { + case MAKE_PROPAGATION_UNCHANGED: + kattr->propagation = 0; + break; + case MAKE_PROPAGATION_UNBINDABLE: + kattr->propagation = MS_UNBINDABLE; + break; + case MAKE_PROPAGATION_PRIVATE: + kattr->propagation = MS_PRIVATE; + break; + case MAKE_PROPAGATION_DEPENDENT: + kattr->propagation = MS_SLAVE; + break; + case MAKE_PROPAGATION_SHARED: + kattr->propagation = MS_SHARED; + break; + default: + return -EINVAL; + } + + if (upper_32_bits(attr->attr_set)) + return -EINVAL; + if (build_attr_flags(lower_32_bits(attr->attr_set), &kattr->attr_set)) + return -EINVAL; + + if (upper_32_bits(attr->attr_clr)) + return -EINVAL; + if (build_attr_flags(lower_32_bits(attr->attr_clr), &kattr->attr_clr)) + return -EINVAL; + + /* + * Since the MOUNT_ATTR_<atime> values are an enum, not a bitmap, users + * wanting to transition to a different atime setting cannot simply + * specify the atime setting in @attr_set, but must also specify + * MOUNT_ATTR__ATIME in the @attr_clr field. + * So ensure that MOUNT_ATTR__ATIME can't be partially set in + * @attr_clr and that @attr_set can't have any atime bits set if + * MOUNT_ATTR__ATIME isn't set in @attr_clr. + */ + if (!(attr->attr_clr & MOUNT_ATTR__ATIME) && (attr->attr_set & MOUNT_ATTR__ATIME)) + return -EINVAL; + else if ((attr->attr_clr & MOUNT_ATTR__ATIME) && + ((attr->attr_clr & MOUNT_ATTR__ATIME) != MOUNT_ATTR__ATIME)) + return -EINVAL; + + if (attr->attr_clr & MOUNT_ATTR__ATIME) { + /* Clear all previous time settings as they are mutually exclusive. */ + kattr->attr_clr |= MNT_RELATIME | MNT_NOATIME; + switch (attr->attr_set & MOUNT_ATTR__ATIME) { + case MOUNT_ATTR_RELATIME: + kattr->attr_set |= MNT_RELATIME; + break; + case MOUNT_ATTR_NOATIME: + kattr->attr_set |= MNT_NOATIME; + break; + case MOUNT_ATTR_STRICTATIME: + break; + default: + return -EINVAL; + } + } + + return 0; +} + +SYSCALL_DEFINE5(mount_setattr, int, dfd, const char __user *, path, unsigned int, flags, + struct mount_attr __user *, uattr, size_t, usize) +{ + int err; + struct path target; + struct mount_attr attr; + struct mount_kattr kattr; + + BUILD_BUG_ON(sizeof(struct mount_attr) < MOUNT_ATTR_SIZE_VER0); + BUILD_BUG_ON(sizeof(struct mount_attr) != MOUNT_ATTR_SIZE_LATEST); + + if (flags & ~(AT_EMPTY_PATH | AT_RECURSIVE | AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT)) + return -EINVAL; + + if (unlikely(usize > PAGE_SIZE)) + return -E2BIG; + if (unlikely(usize < MOUNT_ATTR_SIZE_VER0)) + return -EINVAL; + + if (!may_mount()) + return -EPERM; + + err = copy_struct_from_user(&attr, sizeof(attr), uattr, usize); + if (err) + return err; + + if (attr.attr_set == 0 && attr.attr_clr == 0 && attr.propagation == 0) + return 0; + + err = build_mount_kattr(&attr, &kattr, flags); + if (err) + return err; + + err = user_path_at(dfd, path, kattr.lookup_flags, &target); + if (err) + return err; + + err = do_mount_setattr(&target, &kattr); + path_put(&target); + return err; +} + static void __init init_mount_tree(void) { struct vfsmount *mnt; diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 37bea07c12f2..a62d5904fb6a 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -68,6 +68,7 @@ union bpf_attr; struct io_uring_params; struct clone_args; struct open_how; +struct mount_attr; #include <linux/types.h> #include <linux/aio_abi.h> @@ -999,6 +1000,8 @@ asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags); asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path, int to_dfd, const char __user *to_path, unsigned int ms_flags); +asmlinkage long sys_mount_setattr(int dfd, const char __user *path, unsigned int flags, + struct mount_attr __user *uattr, size_t usize); asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags); asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key, const void __user *value, int aux); diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 2056318988f7..0517f36fe783 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -859,9 +859,11 @@ __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd) __SYSCALL(__NR_faccessat2, sys_faccessat2) #define __NR_process_madvise 440 __SYSCALL(__NR_process_madvise, sys_process_madvise) +#define __NR_mount_setattr 441 +__SYSCALL(__NR_mount_setattr, sys_mount_setattr) #undef __NR_syscalls -#define __NR_syscalls 441 +#define __NR_syscalls 442 /* * 32 bit systems traditionally used different diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h index dd8306ea336c..fba42b4bfc1c 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -1,6 +1,8 @@ #ifndef _UAPI_LINUX_MOUNT_H #define _UAPI_LINUX_MOUNT_H +#include <linux/types.h> + /* * These are the fs-independent mount-flags: up to 32 flags are supported * @@ -118,4 +120,26 @@ enum fsconfig_command { #define MOUNT_ATTR_STRICTATIME 0x00000020 /* - Always perform atime updates */ #define MOUNT_ATTR_NODIRATIME 0x00000080 /* Do not update directory access times */ +/* + * mount_setattr() + */ +struct mount_attr { + __u64 attr_set; + __u64 attr_clr; + __u64 propagation; +}; + +/* Change propagation through mount_setattr(). */ +enum propagation_type { + MAKE_PROPAGATION_UNCHANGED = 0, /* Don't change mount propagation (default). */ + MAKE_PROPAGATION_UNBINDABLE = 1, /* Make unbindable. */ + MAKE_PROPAGATION_PRIVATE = 2, /* Do not receive or send mount events. */ + MAKE_PROPAGATION_DEPENDENT = 3, /* Only receive mount events. */ + MAKE_PROPAGATION_SHARED = 4, /* Send and receive mount events. */ +}; + +/* List of all mount_attr versions. */ +#define MOUNT_ATTR_SIZE_VER0 24 /* sizeof first published struct */ +#define MOUNT_ATTR_SIZE_LATEST MOUNT_ATTR_SIZE_VER0 + #endif /* _UAPI_LINUX_MOUNT_H */ diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h index 2056318988f7..0517f36fe783 100644 --- a/tools/include/uapi/asm-generic/unistd.h +++ b/tools/include/uapi/asm-generic/unistd.h @@ -859,9 +859,11 @@ __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd) __SYSCALL(__NR_faccessat2, sys_faccessat2) #define __NR_process_madvise 440 __SYSCALL(__NR_process_madvise, sys_process_madvise) +#define __NR_mount_setattr 441 +__SYSCALL(__NR_mount_setattr, sys_mount_setattr) #undef __NR_syscalls -#define __NR_syscalls 441 +#define __NR_syscalls 442 /* * 32 bit systems traditionally used different
This implements the missing mount_setattr() syscall. While the new mount api allows to change the properties of a superblock there is currently no way to change the properties of a mount or a mount tree using file descriptors which the new mount api is based on. In addition the old mount api has the restriction that mount options cannot be applied recursively. This hasn't changed since changing mount options on a per-mount basis was implemented in [1] and has been a frequent request not just for convenience but also for security reasons. The legacy mount syscall is unable to accommodate this behavior without introducing a whole new set of flags because MS_REC | MS_REMOUNT | MS_BIND | MS_RDONLY | MS_NOEXEC | [...] only apply the mount option to the topmost mount. Changing MS_REC to apply to the whole mount tree would mean introducing a significant uapi change and would likely cause significant regressions. The new mount_setattr() syscall allows to recursively clear and set mount options in one shot. Multiple calls to change mount options requesting the same changes are idempotent: int mount_setattr(int dfd, const char *path, unsigned flags, struct mount_attr *uattr, size_t usize); Flags to modify path resolution behavior are specified in the @flags argument. Currently, AT_EMPTY_PATH, AT_RECURSIVE, AT_SYMLINK_NOFOLLOW, and AT_NO_AUTOMOUNT are supported. If useful, additional lookup flags to restrict path resolution as introduced with openat2() might be supported in the future. The mount_setattr() syscall can be expected to grow over time and is designed with extensibility in mind. It follows the extensible syscall pattern we have used with other syscalls such as openat2(), clone3(), sched_{set,get}attr(), and others. The set of mount options is passed in the uapi struct mount_attr which currently has the following layout: struct mount_attr { __u64 attr_set; __u64 attr_clr; __u32 propagation; }; The @attr_set and @attr_clr members are used to clear and set mount options. This way a user can e.g. request that a set of flags is to be raised such as turning mounts readonly by raising MOUNT_ATTR_RDONLY in @attr_set while at the same time requesting that another set of flags is to be lowered such as removing noexec from a mount tree by specifying MOUNT_ATTR_NOEXEC in @attr_clr. Note, since the MOUNT_ATTR_<atime> values are an enum starting from 0, not a bitmap, users wanting to transition to a different atime setting cannot simply specify the atime setting in @attr_set, but must also specify MOUNT_ATTR__ATIME in the @attr_clr field. So we ensure that MOUNT_ATTR__ATIME can't be partially set in @attr_clr and that @attr_set can't have any atime bits set if MOUNT_ATTR__ATIME isn't set in @attr_clr. The @propagation field lets callers specify the propagation type of a mount tree. Propagation is a single property that has four different settings and as such is not really a flag argument but an enum. Specifically, it would be unclear what setting and clearing propagation settings in combination would amount to. The legacy mount() syscall thus forbids the combination of multiple propagation settings too. The goal is to keep the semantics of mount propagation somewhat simple as they are overly complex as it is. [1]: commit 2e4b7fcd9260 ("[PATCH] r/o bind mounts: honor mount writer counts at remount") Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: linux-api@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> --- /* v2 */ - Christoph Hellwig <hch@lst.de>: - Split into multiple helpers. /* v3 */ - kernel test robot <lkp@intel.com>: - Fix unknown __u64 type by including linux/types.h in linux/mount.h. --- arch/alpha/kernel/syscalls/syscall.tbl | 1 + arch/arm/tools/syscall.tbl | 1 + arch/arm64/include/asm/unistd32.h | 2 + arch/ia64/kernel/syscalls/syscall.tbl | 1 + arch/m68k/kernel/syscalls/syscall.tbl | 1 + arch/microblaze/kernel/syscalls/syscall.tbl | 1 + arch/mips/kernel/syscalls/syscall_n32.tbl | 1 + arch/mips/kernel/syscalls/syscall_n64.tbl | 1 + arch/mips/kernel/syscalls/syscall_o32.tbl | 1 + arch/parisc/kernel/syscalls/syscall.tbl | 1 + arch/powerpc/kernel/syscalls/syscall.tbl | 1 + arch/s390/kernel/syscalls/syscall.tbl | 1 + arch/sh/kernel/syscalls/syscall.tbl | 1 + arch/sparc/kernel/syscalls/syscall.tbl | 1 + arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/xtensa/kernel/syscalls/syscall.tbl | 1 + fs/internal.h | 8 + fs/namespace.c | 327 ++++++++++++++++++-- include/linux/syscalls.h | 3 + include/uapi/asm-generic/unistd.h | 4 +- include/uapi/linux/mount.h | 24 ++ tools/include/uapi/asm-generic/unistd.h | 4 +- 23 files changed, 362 insertions(+), 26 deletions(-)