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Subject[PATCH] powerpc/rtas_flash: fix a potential buffer overflow
Date
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@huawei.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
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