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authorVasily Averin <vvs@virtuozzo.com>2020-02-01 10:47:47 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-10-01 11:11:52 +0200
commit31edd08c820e1186af6510a1bc0f8bfcbd216a70 (patch)
tree54f40b279d517758b1c9362a0bf437afa8332d6d /security
parentb0dd4542e17fc88ac464f5243ae2da3e84f21f27 (diff)
selinux: sel_avc_get_stat_idx should increase position index
[ Upstream commit 8d269a8e2a8f0bca89022f4ec98de460acb90365 ] If seq_file .next function does not change position index, read after some lseek can generate unexpected output. $ dd if=/sys/fs/selinux/avc/cache_stats # usual output lookups hits misses allocations reclaims frees 817223 810034 7189 7189 6992 7037 1934894 1926896 7998 7998 7632 7683 1322812 1317176 5636 5636 5456 5507 1560571 1551548 9023 9023 9056 9115 0+1 records in 0+1 records out 189 bytes copied, 5,1564e-05 s, 3,7 MB/s $# read after lseek to midle of last line $ dd if=/sys/fs/selinux/avc/cache_stats bs=180 skip=1 dd: /sys/fs/selinux/avc/cache_stats: cannot skip to specified offset 056 9115 <<<< end of last line 1560571 1551548 9023 9023 9056 9115 <<< whole last line once again 0+1 records in 0+1 records out 45 bytes copied, 8,7221e-05 s, 516 kB/s $# read after lseek beyond end of of file $ dd if=/sys/fs/selinux/avc/cache_stats bs=1000 skip=1 dd: /sys/fs/selinux/avc/cache_stats: cannot skip to specified offset 1560571 1551548 9023 9023 9056 9115 <<<< generates whole last line 0+1 records in 0+1 records out 36 bytes copied, 9,0934e-05 s, 396 kB/s https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/selinuxfs.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index c02da25d7b63..7778e28cce9d 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1370,6 +1370,7 @@ static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx)
*idx = cpu + 1;
return &per_cpu(avc_cache_stats, cpu);
}
+ (*idx)++;
return NULL;
}