| Message ID | 20200406120312.1150405-3-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/6] powerpc/spufs: simplify spufs core dumping | expand |
On Mon, Apr 6, 2020 at 2:03 PM Christoph Hellwig <hch@lst.de> wrote: > > Instead of messing with the address limit just open code the trivial > memcpy + memset logic. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/binfmt_elf.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index f4713ea76e82..d744ce9a4b52 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -1556,10 +1556,9 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) > static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, > const kernel_siginfo_t *siginfo) > { > - mm_segment_t old_fs = get_fs(); > - set_fs(KERNEL_DS); > - copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo); > - set_fs(old_fs); > + memcpy(csigdata, siginfo, sizeof(struct kernel_siginfo)); > + memset((char *)csigdata + sizeof(struct kernel_siginfo), 0, > + SI_EXPANSION_SIZE); > fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); > } I think this breaks compat binfmt-elf mode, which relies on this trick: fs/compat_binfmt_elf.c:#define copy_siginfo_to_user copy_siginfo_to_user32 fs/compat_binfmt_elf.c#include "binfmt_elf.c" At least we seem to only have one remaining implementation of __copy_siginfo_to_user32(), so fixing this won't require touching all architectures, but I don't see an obvious way to do it right. Maybe compat-binfmt-elf.c should just override fill_siginfo_note() itself rather than overriding copy_siginfo_to_user(). Arnd
On Mon, Apr 06, 2020 at 03:01:24PM +0200, Arnd Bergmann wrote: > > static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, > > const kernel_siginfo_t *siginfo) > > { > > - mm_segment_t old_fs = get_fs(); > > - set_fs(KERNEL_DS); > > - copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo); > > - set_fs(old_fs); > > + memcpy(csigdata, siginfo, sizeof(struct kernel_siginfo)); > > + memset((char *)csigdata + sizeof(struct kernel_siginfo), 0, > > + SI_EXPANSION_SIZE); > > fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); > > } > > I think this breaks compat binfmt-elf mode, which relies on this trick: > > fs/compat_binfmt_elf.c:#define copy_siginfo_to_user copy_siginfo_to_user32 > fs/compat_binfmt_elf.c#include "binfmt_elf.c" > > At least we seem to only have one remaining implementation of > __copy_siginfo_to_user32(), so fixing this won't require touching all > architectures, but I don't see an obvious way to do it right. Maybe > compat-binfmt-elf.c should just override fill_siginfo_note() itself > rather than overriding copy_siginfo_to_user(). Ooops. Yes, this will need some manual handling.
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f4713ea76e82..d744ce9a4b52 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1556,10 +1556,9 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, const kernel_siginfo_t *siginfo) { - mm_segment_t old_fs = get_fs(); - set_fs(KERNEL_DS); - copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo); - set_fs(old_fs); + memcpy(csigdata, siginfo, sizeof(struct kernel_siginfo)); + memset((char *)csigdata + sizeof(struct kernel_siginfo), 0, + SI_EXPANSION_SIZE); fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); }
Instead of messing with the address limit just open code the trivial memcpy + memset logic. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/binfmt_elf.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)