From patchwork Fri Feb 3 01:34:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. 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R. Silva" To: Amitkumar Karwar , Ganapathi Bhat , Sharvari Harisangam , Xinming Hu , Kalle Valo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] wifi: mwifiex: Replace one-element array with flexible-array member Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org One-element arrays are deprecated, and we are replacing them with flexible array members instead. So, replace one-element array with flexible-array member in struct mwifiex_ie_types_rates_param_set. These are the only binary differences I see after the change: mwifiex.o _@@ -50154,7 +50154,7 @@ 23514: R_X86_64_32S kmalloc_caches+0x50 23518: call 2351d 23519: R_X86_64_PLT32 __tsan_read8-0x4 - 2351d: mov $0x225,%edx + 2351d: mov $0x224,%edx 23522: mov $0xdc0,%esi 23527: mov 0x0(%rip),%rdi # 2352e 2352a: R_X86_64_PC32 kmalloc_caches+0x4c scan.o _@@ -5582,7 +5582,7 @@ 4394: R_X86_64_32S kmalloc_caches+0x50 4398: call 439d 4399: R_X86_64_PLT32 __tsan_read8-0x4 - 439d: mov $0x225,%edx + 439d: mov $0x224,%edx 43a2: mov $0xdc0,%esi 43a7: mov 0x0(%rip),%rdi # 43ae 43aa: R_X86_64_PC32 kmalloc_caches+0x4c and the reason for that is the following line: drivers/net/wireless/marvell/mwifiex/scan.c: 1517 scan_cfg_out = kzalloc(sizeof(union mwifiex_scan_cmd_config_tlv), 1518 GFP_KERNEL); sizeof(union mwifiex_scan_cmd_config_tlv) is now one-byte smaller due to the flex-array transformation: 46 union mwifiex_scan_cmd_config_tlv { 47 /* Scan configuration (variable length) */ 48 struct mwifiex_scan_cmd_config config; 49 /* Max allocated block */ 50 u8 config_alloc_buf[MAX_SCAN_CFG_ALLOC]; 51 }; Notice that MAX_SCAN_CFG_ALLOC is defined in terms of sizeof(struct mwifiex_ie_types_rates_param_set), see: 26 /* Memory needed to store supported rate */ 27 #define RATE_TLV_MAX_SIZE (sizeof(struct mwifiex_ie_types_rates_param_set) \ 28 + HOSTCMD_SUPPORTED_RATES) 37 /* Maximum memory needed for a mwifiex_scan_cmd_config with all TLVs at max */ 38 #define MAX_SCAN_CFG_ALLOC (sizeof(struct mwifiex_scan_cmd_config) \ 39 + sizeof(struct mwifiex_ie_types_num_probes) \ 40 + sizeof(struct mwifiex_ie_types_htcap) \ 41 + CHAN_TLV_MAX_SIZE \ 42 + RATE_TLV_MAX_SIZE \ 43 + WILDCARD_SSID_TLV_MAX_SIZE) This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy() and help us make progress towards globally enabling -fstrict-flex-arrays=3 [1]. Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/252 Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook --- drivers/net/wireless/marvell/mwifiex/fw.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h index 9616bd8b49f1..8c7c744683bc 100644 --- a/drivers/net/wireless/marvell/mwifiex/fw.h +++ b/drivers/net/wireless/marvell/mwifiex/fw.h @@ -794,7 +794,7 @@ struct mwifiex_ie_types_chan_band_list_param_set { struct mwifiex_ie_types_rates_param_set { struct mwifiex_ie_types_header header; - u8 rates[1]; + u8 rates[]; } __packed; struct mwifiex_ie_types_ssid_param_set {