Messages in this thread Patch in this message | | | Date | Fri, 27 Jun 2014 12:31:41 -0400 | From | Vivek Goyal <> | Subject | Re: [PATCH 09/15] kexec: Implementation of new syscall kexec_file_load |
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On Thu, Jun 26, 2014 at 01:58:26PM -0700, Andrew Morton wrote:
[..] > > + while (pos < stat.size) { > > + bytes = kernel_read(f.file, pos, (char *)(*buf) + pos, > > + stat.size - pos); > > + if (bytes < 0) { > > + vfree(*buf); > > + ret = bytes; > > + goto out; > > + } > > + > > + if (bytes == 0) > > + break; > > Here we can get a short read: (pos < stat.size). Seems to me that it > is risky to return this result to the caller as if all is well.
Hi Andrew,
That's a good point. Please find attached the patch which fixes both the issues.
Thanks Vivek
Subject: kexec: Return error if file bytes are less then file size
If number of bytes read from file are not same as file size, return error.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com> --- kernel/kexec.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
Index: linux-2.6/kernel/kexec.c =================================================================== --- linux-2.6.orig/kernel/kexec.c 2014-06-27 09:55:41.826755422 -0400 +++ linux-2.6/kernel/kexec.c 2014-06-27 10:04:23.409024171 -0400 @@ -343,7 +343,7 @@ out_free_image: static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len) { struct fd f = fdget(fd); - int ret = 0; + int ret; struct kstat stat; loff_t pos; ssize_t bytes = 0; @@ -387,6 +387,12 @@ static int copy_file_from_fd(int fd, voi pos += bytes; } + if (pos != stat.size) { + ret = -EBADF; + vfree(*buf); + goto out; + } + *buf_len = pos; out: fdput(f);
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