From: Yi Zhuang <zhuangyi1@huawei.com>
To: <benh@kernel.crashing.org>, <paulus@samba.org>
Cc: <zhuangyi1@huawei.com>, <hegdevasant@linux.vnet.ibm.com>,
<mpe@ellerman.id.au>, <linuxppc-dev@lists.ozlabs.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH v2] powerpc/rtas_flash: fix a potential buffer overflow
Date: Wed, 14 Jul 2021 20:27:53 +0800 [thread overview]
Message-ID: <20210714122753.76021-1-zhuangyi1@huawei.com> (raw)
Since snprintf() returns the possible output size instead of the
actual output size, the available flash_msg length returned by
get_validate_flash_msg may exceed the given buffer limit when
simple_read_from_buffer calls copy_to_user
Reported-by: kernel test robot <lkp@intel.com>
Fixes: a94a14720eaf5 powerpc/rtas_flash: Fix validate_flash buffer overflow issue
Signed-off-by: Yi Zhuang <zhuangyi1@huawei.com>
---
arch/powerpc/kernel/rtas_flash.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c
index a99179d83538..062f0724c2ff 100644
--- a/arch/powerpc/kernel/rtas_flash.c
+++ b/arch/powerpc/kernel/rtas_flash.c
@@ -470,9 +470,14 @@ static int get_validate_flash_msg(struct rtas_validate_flash_t *args_buf,
if (args_buf->status >= VALIDATE_TMP_UPDATE) {
n = sprintf(msg, "%d\n", args_buf->update_results);
if ((args_buf->update_results >= VALIDATE_CUR_UNKNOWN) ||
- (args_buf->update_results == VALIDATE_TMP_UPDATE))
+ (args_buf->update_results == VALIDATE_TMP_UPDATE)) {
n += snprintf(msg + n, msglen - n, "%s\n",
args_buf->buf);
+ if (n >= msglen) {
+ n = msglen;
+ printk(KERN_ERR "FLASH: msg too long.\n");
+ }
+ }
} else {
n = sprintf(msg, "%d\n", args_buf->status);
}
--
2.26.0.106.g9fadedd
next reply other threads:[~2021-07-14 12:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 12:27 Yi Zhuang [this message]
2021-07-14 16:52 ` [PATCH v2] powerpc/rtas_flash: fix a potential buffer overflow Christophe Leroy
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