From ca2b45936522f128c6b7b26399fb316be2f35af1 Mon Sep 17 00:00:00 2001 From: Vasily Averin Date: Sat, 25 Jan 2020 12:10:02 +0300 Subject: [PATCH] bpf: map_seq_next should always increase position index [ Upstream commit 90435a7891a2259b0f74c5a1bc5600d0d64cba8f ] 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 Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/eca84fdd-c374-a154-d874-6c7b55fc3bc4@virtuozzo.com Signed-off-by: Sasha Levin --- kernel/bpf/inode.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index dc9d7ac..c04815b 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -198,6 +198,7 @@ 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; @@ -210,8 +211,6 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) map_iter(m)->done = true; return NULL; } - - ++(*pos); return key; } -- 2.7.4