Commit a1b3d2f2 authored Sep 20, 2018 by Dominique Martinet Committed by Greg Kroah-Hartman Sep 20, 2018

fs/proc/kcore.c: fix invalid memory access in multi-page read optimization

The 'm' kcore_list item could point to kclist_head, and it is incorrect to
look at m->addr / m->size in this case.

There is no choice but to run through the list of entries for every
address if we did not find any entry in the previous iteration

Reset 'm' to NULL in that case at Omar Sandoval's suggestion.

[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/1536100702-28706-1-git-send-email-asmadeus@codewreck.org


Fixes: bf991c22 ("proc/kcore: optimize multiple page reads")
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Omar Sandoval <osandov@osandov.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 889c695d

fs/proc/kcore.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -464,6 +464,7 @@ read_kcore(struct file file, char __user buffer, size_t buflen, loff_t *fpos)
		ret = -EFAULT;
		goto out;
		}
		m = NULL; /* skip the list anchor */
		} else if (m->type == KCORE_VMALLOC) {
		vread(buf, (char *)start, tsz);
		/* we have to zero-fill user buffer even if no read */

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