6.6-stable review patch. If anyone has any objections, please let me know.
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From: Fedor Pchelkin pchelkin@ispras.ru
[ Upstream commit 1342ad786073e96fa813ad943c19f586157ae297 ]
If we fail to unpack the transition table then the table elements which have been already allocated are not freed on error path.
unreferenced object 0xffff88802539e000 (size 128): comm "apparmor_parser", pid 903, jiffies 4294914938 (age 35.085s) hex dump (first 32 bytes): 20 73 6f 6d 65 20 6e 61 73 74 79 20 73 74 72 69 some nasty stri 6e 67 20 73 6f 6d 65 20 6e 61 73 74 79 20 73 74 ng some nasty st backtrace: [<ffffffff81ddb312>] __kmem_cache_alloc_node+0x1e2/0x2d0 [<ffffffff81c47194>] __kmalloc_node_track_caller+0x54/0x170 [<ffffffff81c225b9>] kmemdup+0x29/0x60 [<ffffffff83e1ee65>] aa_unpack_strdup+0xe5/0x1b0 [<ffffffff83e20808>] unpack_pdb+0xeb8/0x2700 [<ffffffff83e23567>] unpack_profile+0x1507/0x4a30 [<ffffffff83e27bfa>] aa_unpack+0x36a/0x1560 [<ffffffff83e194c3>] aa_replace_profiles+0x213/0x33c0 [<ffffffff83de9461>] policy_update+0x261/0x370 [<ffffffff83de978e>] profile_replace+0x20e/0x2a0 [<ffffffff81eac8bf>] vfs_write+0x2af/0xe00 [<ffffffff81eaddd6>] ksys_write+0x126/0x250 [<ffffffff88f34fb6>] do_syscall_64+0x46/0xf0 [<ffffffff890000ea>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
Call aa_free_str_table() on error path as was done before the blamed commit. It implements all necessary checks, frees str_table if it is available and nullifies the pointers.
Found by Linux Verification Center (linuxtesting.org).
Fixes: a0792e2ceddc ("apparmor: make transition table unpack generic so it can be reused") Signed-off-by: Fedor Pchelkin pchelkin@ispras.ru Signed-off-by: John Johansen john.johansen@canonical.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/apparmor/lib.c | 1 + security/apparmor/policy_unpack.c | 7 +++---- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/security/apparmor/lib.c b/security/apparmor/lib.c index c87bccafff44..7182a8b821fb 100644 --- a/security/apparmor/lib.c +++ b/security/apparmor/lib.c @@ -41,6 +41,7 @@ void aa_free_str_table(struct aa_str_table *t) kfree_sensitive(t->table[i]); kfree_sensitive(t->table); t->table = NULL; + t->size = 0; } }
diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c index dbc83455d900..a904bca24026 100644 --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -478,6 +478,8 @@ static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs) if (!table) goto fail;
+ strs->table = table; + strs->size = size; for (i = 0; i < size; i++) { char *str; int c, j, pos, size2 = aa_unpack_strdup(e, &str, NULL); @@ -520,14 +522,11 @@ static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs) goto fail; if (!aa_unpack_nameX(e, AA_STRUCTEND, NULL)) goto fail; - - strs->table = table; - strs->size = size; } return true;
fail: - kfree_sensitive(table); + aa_free_str_table(strs); e->pos = saved_pos; return false; }