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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id s1sm6009223pjz.42.2021.02.11.12.37.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Feb 2021 12:37:18 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org, Mark Brown Cc: Kees Cook , Serge Semin , Ramil Zaripov , "Gustavo A. R. Silva" , linux-spi@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] spi: dw: Avoid stack content exposure Date: Thu, 11 Feb 2021 12:37:14 -0800 Message-Id: <20210211203714.1929862-1-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=c096925a3c8985c42f6bdce7c1dc78eabf32a678; i=ACsCAAtHySWi4/GyQJ4FPUqzRVqKGJseolXprmVqVo0=; m=ssMcO9+CE4ZCEW+w5qXFX6Gk6yDhsXYySpOVbzwhQXs=; p=4UX3omQoBN9kpGxRRn7MGtHp0PfSA3+8vaFM2wXCPcs= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmAllXoACgkQiXL039xtwCb2nA/9ER3 P8/seL8bh2p+NxuRip48LLX1pasXUciBYzdnQ2gykRsTcWSc74DMtIfQkvibEQwjVS7Fdk6tHg+la pWJAiy9KxO3RYWZiq2Bc42Bv0kITcvQkn9NAxUzmBRMuJzbEFp7lOErLuuPy1GJw9cIFfYDFZo3Ow ky0whXUtjbzVpeSL16pg7pRdJhFvnGguV7Dz+sShfopgUpBVdIW+/hfxhiHiMKhjxzxWQd97+4S6x 4543Ba1XY9ij/P66g9In4Q0pBT+/0C9xCBF+0QrAcW43zPlgzcFjiOdlYu4cxvrwd4Oc1maRihxy/ d7YtuBRnmM/28hzvwG0SkFzKpnOWWBS4aR5A54lVrncQp8csikHnrRh/R4s4Wyrypuhxmcc62FPwX 7o86BzsAzi+0ESiivTyHkPcP3+p4MjEjt/EMpPSJ6xlDoUWGirhLt+380ZiaDpEsUACHMIzvoWATK Oq4gW8T9HNWbYEPlMaQ3MF0Sr9Sj+SfJ7yFspxveplbW1PhG9IgYMGN31pkUFlNgkhSf/jpBIjDZr Ymhc8WMK3axbWNX7rzYiz0VfPBUse30A85+WVfzP0Dwv2lb+UdjHEQl9+f95vZAyAKZ3GS0tRgVbi zebE19BkoKQEhrL6E9yYaWWT36/73azQfHCrWPw++0aJVtPFj0ip/y4BgCh6Xa8E= Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Since "data" is u32, &data is a "u32 *" type, which means pointer math will move in u32-sized steps. This was meant to be a byte offset, so cast &data to "char *" to aim the copy into the correct location. Seen with -Warray-bounds (and found by Coverity): In file included from ./include/linux/string.h:269, from ./arch/powerpc/include/asm/paca.h:15, from ./arch/powerpc/include/asm/current.h:13, from ./include/linux/mutex.h:14, from ./include/linux/notifier.h:14, from ./include/linux/clk.h:14, from drivers/spi/spi-dw-bt1.c:12: In function 'memcpy', inlined from 'dw_spi_bt1_dirmap_copy_from_map' at drivers/spi/spi-dw-bt1.c:87:3: ./include/linux/fortify-string.h:20:29: warning: '__builtin_memcpy' offset 4 is out of the bounds [0, 4] of object 'data' with type 'u32' {aka 'unsigned int'} [-Warray-bounds] 20 | #define __underlying_memcpy __builtin_memcpy | ^ ./include/linux/fortify-string.h:191:9: note: in expansion of macro '__underlying_memcpy' 191 | return __underlying_memcpy(p, q, size); | ^~~~~~~~~~~~~~~~~~~ drivers/spi/spi-dw-bt1.c: In function 'dw_spi_bt1_dirmap_copy_from_map': drivers/spi/spi-dw-bt1.c:77:6: note: 'data' declared here 77 | u32 data; | ^~~~ Addresses-Coverity: CID 1497771 Out-of-bounds access Fixes: abf00907538e ("spi: dw: Add Baikal-T1 SPI Controller glue driver") Signed-off-by: Kees Cook --- drivers/spi/spi-dw-bt1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-dw-bt1.c b/drivers/spi/spi-dw-bt1.c index 4aa8596fb1f2..5be6b7b80c21 100644 --- a/drivers/spi/spi-dw-bt1.c +++ b/drivers/spi/spi-dw-bt1.c @@ -84,7 +84,7 @@ static void dw_spi_bt1_dirmap_copy_from_map(void *to, void __iomem *from, size_t if (shift) { chunk = min_t(size_t, 4 - shift, len); data = readl_relaxed(from - shift); - memcpy(to, &data + shift, chunk); + memcpy(to, (char *)&data + shift, chunk); from += chunk; to += chunk; len -= chunk; -- 2.25.1