Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Ronald Monthero <> | Subject | [PATCH] qnx4: fix to avoid panic due to buffer overflow | Date | Sun, 12 Nov 2023 19:53:53 +1000 |
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qnx4 dir name length can vary to be of maximum size QNX4_NAME_MAX or QNX4_SHORT_NAME_MAX depending on whether 'link info' entry is stored and the status byte is set. So to avoid buffer overflow check di_fname length fetched from (struct qnx4_inode_entry *) before use in strlen to avoid buffer overflow.
panic context [ 4849.636861] detected buffer overflow in strlen [ 4849.636897] ------------[ cut here ]------------ [ 4849.636902] kernel BUG at lib/string.c:1165! [ 4849.636917] invalid opcode: 0000 [#2] SMP PTI .. [ 4849.637047] Call Trace: [ 4849.637053] <TASK> [ 4849.637059] ? show_trace_log_lvl+0x1d6/0x2ea [ 4849.637075] ? show_trace_log_lvl+0x1d6/0x2ea [ 4849.637095] ? qnx4_find_entry.cold+0xc/0x18 [qnx4] [ 4849.637111] ? show_regs.part.0+0x23/0x29 [ 4849.637123] ? __die_body.cold+0x8/0xd [ 4849.637135] ? __die+0x2b/0x37 [ 4849.637147] ? die+0x30/0x60 [ 4849.637161] ? do_trap+0xbe/0x100 [ 4849.637171] ? do_error_trap+0x6f/0xb0 [ 4849.637180] ? fortify_panic+0x13/0x15 [ 4849.637192] ? exc_invalid_op+0x53/0x70 [ 4849.637203] ? fortify_panic+0x13/0x15 [ 4849.637215] ? asm_exc_invalid_op+0x1b/0x20 [ 4849.637228] ? fortify_panic+0x13/0x15 [ 4849.637240] ? fortify_panic+0x13/0x15 [ 4849.637251] qnx4_find_entry.cold+0xc/0x18 [qnx4] [ 4849.637264] qnx4_lookup+0x3c/0xa0 [qnx4] [ 4849.637275] __lookup_slow+0x85/0x150 [ 4849.637291] walk_component+0x145/0x1c0 [ 4849.637304] ? path_init+0x2c0/0x3f0 [ 4849.637316] path_lookupat+0x6e/0x1c0 [ 4849.637330] filename_lookup+0xcf/0x1d0 [ 4849.637341] ? __check_object_size+0x1d/0x30 [ 4849.637354] ? strncpy_from_user+0x44/0x150 [ 4849.637365] ? getname_flags.part.0+0x4c/0x1b0 [ 4849.637375] user_path_at_empty+0x3f/0x60 [ 4849.637383] vfs_statx+0x7a/0x130 [ 4849.637393] do_statx+0x45/0x80 ..
Signed-off-by: Ronald Monthero <debug.penguin32@gmail.com> --- fs/qnx4/namei.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/fs/qnx4/namei.c b/fs/qnx4/namei.c index 8d72221735d7..825b891a52b3 100644 --- a/fs/qnx4/namei.c +++ b/fs/qnx4/namei.c @@ -40,6 +40,13 @@ static int qnx4_match(int len, const char *name, } else { namelen = QNX4_SHORT_NAME_MAX; } + + /** qnx4 dir name length can vary, check the di_fname + * fetched from (struct qnx4_inode_entry *) before use in + * strlen to avoid panic due to buffer overflow" + */ + if (strnlen(de->di_fname, namelen) >= sizeof(de->di_fname)) + return -ENAMETOOLONG; thislen = strlen( de->di_fname ); if ( thislen > namelen ) thislen = namelen; -- 2.34.1
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