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authorVasily Averin2020-01-25 12:10:02 +0300
committerDaniel Borkmann2020-01-27 10:54:32 +0100
commit90435a7891a2259b0f74c5a1bc5600d0d64cba8f (patch)
treedcaf37c1d2dd0a92827364fd29a3c1f783fe7ba0 /kernel/bpf
parent07fdbee134b3530ef30c709aa4251ca04ea9e3f8 (diff)
bpf: map_seq_next should always increase position index
If seq_file .next fuction does not change position index, read after some lseek can generate an unexpected output. See also: https://bugzilla.kernel.org/show_bug.cgi?id=206283 v1 -> v2: removed missed increment in end of function Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/eca84fdd-c374-a154-d874-6c7b55fc3bc4@virtuozzo.com
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/inode.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index e11059b99f18..bd2fd8eab470 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -196,6 +196,7 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos)
void *key = map_iter(m)->key;
void *prev_key;
+ (*pos)++;
if (map_iter(m)->done)
return NULL;
@@ -208,8 +209,6 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos)
map_iter(m)->done = true;
return NULL;
}
-
- ++(*pos);
return key;
}