linux-kernel - [PATCH] powerpc/rtas_flash: fix a potential buffer overflow

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210714011608.15043-1-zhuangyi1@huawei.com>
Date:   Wed, 14 Jul 2021 09:16:08 +0800
From:   Yi Zhuang <zhuangyi1@...wei.com>
To:     <benh@...nel.crashing.org>, <paulus@...ba.org>
CC:     <zhuangyi1@...wei.com>, <hegdevasant@...ux.vnet.ibm.com>,
        <mpe@...erman.id.au>, <linuxppc-dev@...ts.ozlabs.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] powerpc/rtas_flash: fix a potential buffer overflow

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

Signed-off-by: Yi Zhuang <zhuangyi1@...wei.com>
---
 arch/powerpc/kernel/rtas_flash.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c
index a99179d83538..4aa6bad28556 100644
--- a/arch/powerpc/kernel/rtas_flash.c
+++ b/arch/powerpc/kernel/rtas_flash.c
@@ -473,6 +473,10 @@ static int get_validate_flash_msg(struct rtas_validate_flash_t *args_buf,
 		    (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