* FAILED: patch "[PATCH] mm/usercopy: use memory range to be accessed for wraparound" failed to apply to 4.14-stable tree
@ 2019-08-16 10:04 gregkh
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From: gregkh @ 2019-08-16 10:04 UTC (permalink / raw)
To: isaacm, akpm, gregkh, keescook, psodagud, stable, torvalds,
tsoni, william.kucharski
Cc: stable
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 951531691c4bcaa59f56a316e018bc2ff1ddf855 Mon Sep 17 00:00:00 2001
From: "Isaac J. Manjarres" <isaacm@codeaurora.org>
Date: Tue, 13 Aug 2019 15:37:37 -0700
Subject: [PATCH] mm/usercopy: use memory range to be accessed for wraparound
check
Currently, when checking to see if accessing n bytes starting at address
"ptr" will cause a wraparound in the memory addresses, the check in
check_bogus_address() adds an extra byte, which is incorrect, as the
range of addresses that will be accessed is [ptr, ptr + (n - 1)].
This can lead to incorrectly detecting a wraparound in the memory
address, when trying to read 4 KB from memory that is mapped to the the
last possible page in the virtual address space, when in fact, accessing
that range of memory would not cause a wraparound to occur.
Use the memory range that will actually be accessed when considering if
accessing a certain amount of bytes will cause the memory address to
wrap around.
Link: http://lkml.kernel.org/r/1564509253-23287-1-git-send-email-isaacm@codeaurora.org
Fixes: f5509cc18daa ("mm: Hardened usercopy")
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Co-developed-by: Prasad Sodagudi <psodagud@codeaurora.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Trilok Soni <tsoni@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/usercopy.c b/mm/usercopy.c
index 2a09796edef8..98e924864554 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -147,7 +147,7 @@ static inline void check_bogus_address(const unsigned long ptr, unsigned long n,
bool to_user)
{
/* Reject if object wraps past end of memory. */
- if (ptr + n < ptr)
+ if (ptr + (n - 1) < ptr)
usercopy_abort("wrapped address", NULL, to_user, 0, ptr + n);
/* Reject if NULL or ZERO-allocation. */
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2019-08-16 10:04 FAILED: patch "[PATCH] mm/usercopy: use memory range to be accessed for wraparound" failed to apply to 4.14-stable tree gregkh
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