From: Yun Zhou yun.zhou@windriver.com
stable inclusion from linux-4.19.198 commit 1f4c6061fccee64b2072b28dfa3e93cf859c4c0a
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commit d3b16034a24a112bb83aeb669ac5b9b01f744bb7 upstream.
There's two variables being increased in that loop (i and j), and i follows the raw data, and j follows what is being written into the buffer. We should compare 'i' to MAX_MEMHEX_BYTES or compare 'j' to HEX_CHARS. Otherwise, if 'j' goes bigger than HEX_CHARS, it will overflow the destination buffer.
Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@oasis.local.home/ Link: https://lkml.kernel.org/r/20210626032156.47889-1-yun.zhou@windriver.com
Cc: stable@vger.kernel.org Fixes: 5e3ca0ec76fce ("ftrace: introduce the "hex" output method") Signed-off-by: Yun Zhou yun.zhou@windriver.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- lib/seq_buf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/seq_buf.c b/lib/seq_buf.c index b15dbb6f061a5..5dd4d1d02a175 100644 --- a/lib/seq_buf.c +++ b/lib/seq_buf.c @@ -228,8 +228,10 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
WARN_ON(s->size == 0);
+ BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS); + while (len) { - start_len = min(len, HEX_CHARS - 1); + start_len = min(len, MAX_MEMHEX_BYTES); #ifdef __BIG_ENDIAN for (i = 0, j = 0; i < start_len; i++) { #else