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author | Isaac J. Manjarres <isaacm@codeaurora.org> | 2019-08-14 01:37:37 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-08-14 02:06:52 +0300 |
commit | 951531691c4bcaa59f56a316e018bc2ff1ddf855 (patch) | |
tree | a26a939586580ccb3c570a558a58f138c55c19af /mm/workingset.c | |
parent | fcf3a5b62f431ce9feeac73afbe128b7b6395dbc (diff) | |
download | linux-951531691c4bcaa59f56a316e018bc2ff1ddf855.tar.xz |
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>
Diffstat (limited to 'mm/workingset.c')
0 files changed, 0 insertions, 0 deletions