From a1b3d2f217cf51505858c5c160abef96c3e91721 Mon Sep 17 00:00:00 2001
From: Dominique Martinet <asmadeus@codewreck.org>
Date: Thu, 20 Sep 2018 12:22:35 -0700
Subject: [PATCH] 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>
---
fs/proc/kcore.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index ad72261ee3fe8..d297fe4472a96 100644
--- 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 */
--
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