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authorYun Zhou <yun.zhou@windriver.com>2021-06-26 11:21:55 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-07-19 08:53:16 +0200
commit33ab9138a13e379cf1c4ccd76b97ae2ee8c5421b (patch)
tree6e9e702a4915ec1b582cff1162add0720930c794 /lib
parent854bf719660176592ba3eef4dd63f54b08f311ef (diff)
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seq_buf: Fix overflow in seq_buf_putmem_hex()
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>
Diffstat (limited to 'lib')
-rw-r--r--lib/seq_buf.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/seq_buf.c b/lib/seq_buf.c
index b15dbb6f061a..5dd4d1d02a17 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