ba195a931a
commit d68894800ec5712d7ddf042356f11e36f87d7f78 upstream.
In nfs_idmap_read_and_verify_message there is an incorrect sprintf '%d'
that converts the __u32 'im_id' from struct idmap_msg to 'id_str', which
is a stack char array variable of length NFS_UINT_MAXLEN == 11.
If a uid or gid value is > 2147483647 = 0x7fffffff, the conversion
overflows into a negative value, for example:
crash> p (unsigned) (0x80000000)
$1 = 2147483648
crash> p (signed) (0x80000000)
$2 = -2147483648
The '-' sign is written to the buffer and this causes a 1 byte overflow
when the NULL byte is written, which corrupts kernel stack memory. If
CONFIG_CC_STACKPROTECTOR_STRONG is set we see a stack-protector panic:
[11558053.616565] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffffa05b8a8c
[11558053.639063] CPU: 6 PID: 9423 Comm: rpc.idmapd Tainted: G W ------------ T 3.10.0-514.el7.x86_64 #1
[11558053.641990] Hardware name: Red Hat OpenStack Compute, BIOS 1.10.2-3.el7_4.1 04/01/2014
[11558053.644462] ffffffff818c7bc0 00000000b1f3aec1 ffff880de0f9bd48 ffffffff81685eac
[11558053.646430] ffff880de0f9bdc8 ffffffff8167f2b3 ffffffff00000010 ffff880de0f9bdd8
[11558053.648313] ffff880de0f9bd78 00000000b1f3aec1 ffffffff811dcb03 ffffffffa05b8a8c
[11558053.650107] Call Trace:
[11558053.651347] [<ffffffff81685eac>] dump_stack+0x19/0x1b
[11558053.653013] [<ffffffff8167f2b3>] panic+0xe3/0x1f2
[11558053.666240] [<ffffffff811dcb03>] ? kfree+0x103/0x140
[11558053.682589] [<ffffffffa05b8a8c>] ? idmap_pipe_downcall+0x1cc/0x1e0 [nfsv4]
[11558053.689710] [<ffffffff810855db>] __stack_chk_fail+0x1b/0x30
[11558053.691619] [<ffffffffa05b8a8c>] idmap_pipe_downcall+0x1cc/0x1e0 [nfsv4]
[11558053.693867] [<ffffffffa00209d6>] rpc_pipe_write+0x56/0x70 [sunrpc]
[11558053.695763] [<ffffffff811fe12d>] vfs_write+0xbd/0x1e0
[11558053.702236] [<ffffffff810acccc>] ? task_work_run+0xac/0xe0
[11558053.704215] [<ffffffff811fec4f>] SyS_write+0x7f/0xe0
[11558053.709674] [<ffffffff816964c9>] system_call_fastpath+0x16/0x1b
Fix this by calling the internally defined nfs_map_numeric_to_string()
function which properly uses '%u' to convert this __u32. For consistency,
also replace the one other place where snprintf is called.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Reported-by: Stephen Johnston <sjohnsto@redhat.com>
Fixes:
|
||
|---|---|---|
| .. | ||
| blocklayout | ||
| filelayout | ||
| flexfilelayout | ||
| objlayout | ||
| cache_lib.c | ||
| cache_lib.h | ||
| callback_proc.c | ||
| callback_xdr.c | ||
| callback.c | ||
| callback.h | ||
| client.c | ||
| delegation.c | ||
| delegation.h | ||
| dir.c | ||
| direct.c | ||
| dns_resolve.c | ||
| dns_resolve.h | ||
| file.c | ||
| fscache-index.c | ||
| fscache.c | ||
| fscache.h | ||
| getroot.c | ||
| inode.c | ||
| internal.h | ||
| iostat.h | ||
| Kconfig | ||
| Makefile | ||
| mount_clnt.c | ||
| namespace.c | ||
| netns.h | ||
| nfs.h | ||
| nfs2super.c | ||
| nfs2xdr.c | ||
| nfs3_fs.h | ||
| nfs3acl.c | ||
| nfs3client.c | ||
| nfs3proc.c | ||
| nfs3super.c | ||
| nfs3xdr.c | ||
| nfs4_fs.h | ||
| nfs4client.c | ||
| nfs4file.c | ||
| nfs4getroot.c | ||
| nfs4idmap.c | ||
| nfs4idmap.h | ||
| nfs4namespace.c | ||
| nfs4proc.c | ||
| nfs4renewd.c | ||
| nfs4session.c | ||
| nfs4session.h | ||
| nfs4state.c | ||
| nfs4super.c | ||
| nfs4sysctl.c | ||
| nfs4trace.c | ||
| nfs4trace.h | ||
| nfs4xdr.c | ||
| nfs42.h | ||
| nfs42proc.c | ||
| nfs42xdr.c | ||
| nfsroot.c | ||
| nfstrace.c | ||
| nfstrace.h | ||
| pagelist.c | ||
| pnfs_dev.c | ||
| pnfs_nfs.c | ||
| pnfs.c | ||
| pnfs.h | ||
| proc.c | ||
| read.c | ||
| super.c | ||
| symlink.c | ||
| sysctl.c | ||
| unlink.c | ||
| write.c | ||