Re: [PATCH v2] powerpc/rtas_flash: fix a potential buffer overflow
flat view
From: Christophe Leroy <hidden>
Date: 2021-07-14 16:47:20
Also in:
lkml
Yi Zhuang [off-list ref] a écrit :
quoted hunk ↗ jump to hunk
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 <redacted> Fixes: a94a14720eaf5 powerpc/rtas_flash: Fix validate_flash buffer overflow issue Signed-off-by: Yi Zhuang <redacted> --- 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 cannot be greater than msglen
+ n = msglen;
+ printk(KERN_ERR "FLASH: msg too long.\n");
+ }
+ }
} else {
n = sprintf(msg, "%d\n", args_buf->status);
}
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2.26.0.106.g9fadedd