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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 14:12:33 +0300
commitdd79c17744311f20facf056c0d56a88a48c1c464 (patch)
tree5300b191aca755ad5a0d405d706ea6e55ff50f72 /security/selinux/selinuxfs.c
parent0f789c3a880d4c864384759fd90978f7eb81cc08 (diff)
downloadlinux-dd79c17744311f20facf056c0d56a88a48c1c464.tar.xz
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/selinux/selinuxfs.c')
-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 00eed842c491..bf50fead9f8c 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1425,6 +1425,7 @@ 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;
}