| Message ID | 20210929180654.32460-1-vvidic@valentin-vidic.from.hr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ocfs2: mount fails with buffer overflow in strlen | expand |
On 9/30/21 2:06 AM, Valentin Vidic wrote: > Starting with kernel 5.11 built with CONFIG_FORTIFY_SOURCE mouting an > ocfs2 filesystem with either o2cb or pcmk cluster stack fails with the > trace below. Problem seems to be that strings for cluster stack and > cluster name are not guaranteed to be null terminated in the disk > representation, while strlcpy assumes that the source string is always > null terminated. This causes a read outside of the source string > triggering the buffer overflow detection. > > detected buffer overflow in strlen > ------------[ cut here ]------------ > kernel BUG at lib/string.c:1149! > invalid opcode: 0000 [#1] SMP PTI > CPU: 1 PID: 910 Comm: mount.ocfs2 Not tainted 5.14.0-1-amd64 #1 > Debian 5.14.6-2 > RIP: 0010:fortify_panic+0xf/0x11 > ... > Call Trace: > ocfs2_initialize_super.isra.0.cold+0xc/0x18 [ocfs2] > ocfs2_fill_super+0x359/0x19b0 [ocfs2] > mount_bdev+0x185/0x1b0 > ? ocfs2_remount+0x440/0x440 [ocfs2] > legacy_get_tree+0x27/0x40 > vfs_get_tree+0x25/0xb0 > path_mount+0x454/0xa20 > __x64_sys_mount+0x103/0x140 > do_syscall_64+0x3b/0xc0 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> > --- > v2: update description, add comment, drop null termination > > fs/ocfs2/super.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c > index c86bd4e60e20..5c914ce9b3ac 100644 > --- a/fs/ocfs2/super.c > +++ b/fs/ocfs2/super.c > @@ -2167,11 +2167,17 @@ static int ocfs2_initialize_super(struct super_block *sb, > } > > if (ocfs2_clusterinfo_valid(osb)) { > + /* > + * ci_stack and ci_cluster in ocfs2_cluster_info may not be null > + * terminated, so make sure no overflow happens here by using > + * memcpy. Destination strings will always be null terminated > + * because osb is allocated using kzalloc. > + */ > osb->osb_stackflags = > OCFS2_RAW_SB(di)->s_cluster_info.ci_stackflags; > - strlcpy(osb->osb_cluster_stack, > + memcpy(osb->osb_cluster_stack, > OCFS2_RAW_SB(di)->s_cluster_info.ci_stack, > - OCFS2_STACK_LABEL_LEN + 1); > + OCFS2_STACK_LABEL_LEN); > if (strlen(osb->osb_cluster_stack) != OCFS2_STACK_LABEL_LEN) { > mlog(ML_ERROR, > "couldn't mount because of an invalid " > @@ -2180,9 +2186,9 @@ static int ocfs2_initialize_super(struct super_block *sb, > status = -EINVAL; > goto bail; > } > - strlcpy(osb->osb_cluster_name, > + memcpy(osb->osb_cluster_name, > OCFS2_RAW_SB(di)->s_cluster_info.ci_cluster, > - OCFS2_CLUSTER_NAME_LEN + 1); > + OCFS2_CLUSTER_NAME_LEN); > } else { > /* The empty string is identical with classic tools that > * don't know about s_cluster_info. */ >
Hi Andrew, This panic looks urgent, which is blocking our CI testing for new SLE releases. If possible, please help to merge it to Linus git tree. Thanks Gang On 2021/9/30 9:54, Joseph Qi wrote: > > > On 9/30/21 2:06 AM, Valentin Vidic wrote: >> Starting with kernel 5.11 built with CONFIG_FORTIFY_SOURCE mouting an >> ocfs2 filesystem with either o2cb or pcmk cluster stack fails with the >> trace below. Problem seems to be that strings for cluster stack and >> cluster name are not guaranteed to be null terminated in the disk >> representation, while strlcpy assumes that the source string is always >> null terminated. This causes a read outside of the source string >> triggering the buffer overflow detection. >> >> detected buffer overflow in strlen >> ------------[ cut here ]------------ >> kernel BUG at lib/string.c:1149! >> invalid opcode: 0000 [#1] SMP PTI >> CPU: 1 PID: 910 Comm: mount.ocfs2 Not tainted 5.14.0-1-amd64 #1 >> Debian 5.14.6-2 >> RIP: 0010:fortify_panic+0xf/0x11 >> ... >> Call Trace: >> ocfs2_initialize_super.isra.0.cold+0xc/0x18 [ocfs2] >> ocfs2_fill_super+0x359/0x19b0 [ocfs2] >> mount_bdev+0x185/0x1b0 >> ? ocfs2_remount+0x440/0x440 [ocfs2] >> legacy_get_tree+0x27/0x40 >> vfs_get_tree+0x25/0xb0 >> path_mount+0x454/0xa20 >> __x64_sys_mount+0x103/0x140 >> do_syscall_64+0x3b/0xc0 >> entry_SYSCALL_64_after_hwframe+0x44/0xae >> >> Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr> > > Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> >> --- >> v2: update description, add comment, drop null termination >> >> fs/ocfs2/super.c | 14 ++++++++++---- >> 1 file changed, 10 insertions(+), 4 deletions(-) >> >> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c >> index c86bd4e60e20..5c914ce9b3ac 100644 >> --- a/fs/ocfs2/super.c >> +++ b/fs/ocfs2/super.c >> @@ -2167,11 +2167,17 @@ static int ocfs2_initialize_super(struct super_block *sb, >> } >> >> if (ocfs2_clusterinfo_valid(osb)) { >> + /* >> + * ci_stack and ci_cluster in ocfs2_cluster_info may not be null >> + * terminated, so make sure no overflow happens here by using >> + * memcpy. Destination strings will always be null terminated >> + * because osb is allocated using kzalloc. >> + */ >> osb->osb_stackflags = >> OCFS2_RAW_SB(di)->s_cluster_info.ci_stackflags; >> - strlcpy(osb->osb_cluster_stack, >> + memcpy(osb->osb_cluster_stack, >> OCFS2_RAW_SB(di)->s_cluster_info.ci_stack, >> - OCFS2_STACK_LABEL_LEN + 1); >> + OCFS2_STACK_LABEL_LEN); >> if (strlen(osb->osb_cluster_stack) != OCFS2_STACK_LABEL_LEN) { >> mlog(ML_ERROR, >> "couldn't mount because of an invalid " >> @@ -2180,9 +2186,9 @@ static int ocfs2_initialize_super(struct super_block *sb, >> status = -EINVAL; >> goto bail; >> } >> - strlcpy(osb->osb_cluster_name, >> + memcpy(osb->osb_cluster_name, >> OCFS2_RAW_SB(di)->s_cluster_info.ci_cluster, >> - OCFS2_CLUSTER_NAME_LEN + 1); >> + OCFS2_CLUSTER_NAME_LEN); >> } else { >> /* The empty string is identical with classic tools that >> * don't know about s_cluster_info. */ >> > > _______________________________________________ > Ocfs2-devel mailing list > Ocfs2-devel@oss.oracle.com > https://oss.oracle.com/mailman/listinfo/ocfs2-devel >
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index c86bd4e60e20..5c914ce9b3ac 100644 --- a/fs/ocfs2/super.c +++ b/fs/ocfs2/super.c @@ -2167,11 +2167,17 @@ static int ocfs2_initialize_super(struct super_block *sb, } if (ocfs2_clusterinfo_valid(osb)) { + /* + * ci_stack and ci_cluster in ocfs2_cluster_info may not be null + * terminated, so make sure no overflow happens here by using + * memcpy. Destination strings will always be null terminated + * because osb is allocated using kzalloc. + */ osb->osb_stackflags = OCFS2_RAW_SB(di)->s_cluster_info.ci_stackflags; - strlcpy(osb->osb_cluster_stack, + memcpy(osb->osb_cluster_stack, OCFS2_RAW_SB(di)->s_cluster_info.ci_stack, - OCFS2_STACK_LABEL_LEN + 1); + OCFS2_STACK_LABEL_LEN); if (strlen(osb->osb_cluster_stack) != OCFS2_STACK_LABEL_LEN) { mlog(ML_ERROR, "couldn't mount because of an invalid " @@ -2180,9 +2186,9 @@ static int ocfs2_initialize_super(struct super_block *sb, status = -EINVAL; goto bail; } - strlcpy(osb->osb_cluster_name, + memcpy(osb->osb_cluster_name, OCFS2_RAW_SB(di)->s_cluster_info.ci_cluster, - OCFS2_CLUSTER_NAME_LEN + 1); + OCFS2_CLUSTER_NAME_LEN); } else { /* The empty string is identical with classic tools that * don't know about s_cluster_info. */
Starting with kernel 5.11 built with CONFIG_FORTIFY_SOURCE mouting an ocfs2 filesystem with either o2cb or pcmk cluster stack fails with the trace below. Problem seems to be that strings for cluster stack and cluster name are not guaranteed to be null terminated in the disk representation, while strlcpy assumes that the source string is always null terminated. This causes a read outside of the source string triggering the buffer overflow detection. detected buffer overflow in strlen ------------[ cut here ]------------ kernel BUG at lib/string.c:1149! invalid opcode: 0000 [#1] SMP PTI CPU: 1 PID: 910 Comm: mount.ocfs2 Not tainted 5.14.0-1-amd64 #1 Debian 5.14.6-2 RIP: 0010:fortify_panic+0xf/0x11 ... Call Trace: ocfs2_initialize_super.isra.0.cold+0xc/0x18 [ocfs2] ocfs2_fill_super+0x359/0x19b0 [ocfs2] mount_bdev+0x185/0x1b0 ? ocfs2_remount+0x440/0x440 [ocfs2] legacy_get_tree+0x27/0x40 vfs_get_tree+0x25/0xb0 path_mount+0x454/0xa20 __x64_sys_mount+0x103/0x140 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr> --- v2: update description, add comment, drop null termination fs/ocfs2/super.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)