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commit a1b3d2f217cf51505858c5c160abef96c3e91721
parent 889c695d419f19e5db52592dafbaf26143c36d1f
Author: Dominique Martinet <asmadeus@codewreck.org>
Date:   Thu, 20 Sep 2018 12:22:35 -0700

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: bf991c2231117 ("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>

Mfs/proc/kcore.c | 1+
1 file changed, 1 insertion(+), 0 deletions(-)

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c @@ -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 */