| Message ID | 441c893b-5cfa-1675-c568-2c04b3bb841a@virtuozzo.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] selinux: sel_avc_get_stat_idx should increase position index | expand |
On 2/1/20 2:47 AM, Vasily Averin wrote: > 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> > --- > security/selinux/selinuxfs.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c > index ee94fa4..ad5530e 100644 > --- a/security/selinux/selinuxfs.c > +++ b/security/selinux/selinuxfs.c > @@ -1504,6 +1504,7 @@ 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; > }
On Sat, Feb 1, 2020 at 2:49 AM Vasily Averin <vvs@virtuozzo.com> wrote: > > 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> > --- > security/selinux/selinuxfs.c | 1 + > 1 file changed, 1 insertion(+) This is better, thank you. I've queued this up for selinux/next, you'll see it in the repo once the merge window closes. > diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c > index ee94fa4..ad5530e 100644 > --- a/security/selinux/selinuxfs.c > +++ b/security/selinux/selinuxfs.c > @@ -1504,6 +1504,7 @@ 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; > } > > -- > 1.8.3.1 >
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index ee94fa4..ad5530e 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -1504,6 +1504,7 @@ 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; }
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> --- security/selinux/selinuxfs.c | 1 + 1 file changed, 1 insertion(+)