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author | David Howells <dhowells@redhat.com> | 2018-05-16 23:25:46 +0300 |
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committer | David Howells <dhowells@redhat.com> | 2018-05-16 23:35:23 +0300 |
commit | 378831e4daec75fbba6d3612bcf3b4dd00ddbf08 (patch) | |
tree | 66cdf5ae7efa2fe90491caa6cd15c6158791f17e /fs/afs/dynroot.c | |
parent | 21b9f1c7e319f654de3b2574fe8d4e4114c9143f (diff) | |
download | linux-378831e4daec75fbba6d3612bcf3b4dd00ddbf08.tar.xz |
afs: Fix directory permissions check
Doing faccessat("/afs/some/directory", 0) triggers a BUG in the permissions
check code.
Fix this by just removing the BUG section. If no permissions are asked
for, just return okay if the file exists.
Also:
(1) Split up the directory check so that it has separate if-statements
rather than if-else-if (e.g. checking for MAY_EXEC shouldn't skip the
check for MAY_READ and MAY_WRITE).
(2) Check for MAY_CHDIR as MAY_EXEC.
Without the main fix, the following BUG may occur:
kernel BUG at fs/afs/security.c:386!
invalid opcode: 0000 [#1] SMP PTI
...
RIP: 0010:afs_permission+0x19d/0x1a0 [kafs]
...
Call Trace:
? inode_permission+0xbe/0x180
? do_faccessat+0xdc/0x270
? do_syscall_64+0x60/0x1f0
? entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: 00d3b7a4533e ("[AFS]: Add security support.")
Reported-by: Jonathan Billings <jsbillings@jsbillings.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/dynroot.c')
0 files changed, 0 insertions, 0 deletions