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Wed, 01 Jul 2026 02:56:54 -0700 (PDT) Received: from csl-conti-dell7858.ntu.edu.sg ([155.69.195.57]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8479ff8c62asm3756542b3a.12.2026.07.01.02.56.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Jul 2026 02:56:53 -0700 (PDT) From: Maoyi Xie To: Mauro Carvalho Chehab Cc: Kees Cook , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] media: dib9000: bound the mailbox reply length in dib9000_mbx_get_message_attr Date: Wed, 1 Jul 2026 17:56:49 +0800 Message-Id: <20260701095649.1629460-1-maoyixie.tju@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit dib9000_mbx_get_message_attr() copies a mailbox reply into the caller buffer with a length the demod controls: *size = (*block & 0xff) - 1; memcpy(msg, block + 1, (*size) * 2); *block is a cached mailbox word whose low byte comes from the DiB9000 demod over I2C. *size is a u8. A low byte of 0 wraps to 255, so the memcpy runs 510 bytes. The callers pass small fixed stack buffers. check_version() passes a u8 r[4] and the APB helpers a u16 mb[10], with no check. fw_init() has a check but runs it after the copy. check_version() runs on the firmware boot path, so a normal frontend bring-up reaches it. dib9000_mbx_get_message_attr() now takes the buffer size in words and rejects an oversized reply. Each caller passes its buffer size. Fixes: dd316c6bacc2 ("[media] DIB9000: initial support added") Cc: stable@vger.kernel.org Signed-off-by: Maoyi Xie --- drivers/media/dvb-frontends/dib9000.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/media/dvb-frontends/dib9000.c b/drivers/media/dvb-frontends/dib9000.c index cb7c943225bd3..19c1853e6af2d 100644 --- a/drivers/media/dvb-frontends/dib9000.c +++ b/drivers/media/dvb-frontends/dib9000.c @@ -390,7 +390,7 @@ static inline int dib9000_write_word_attr(struct dib9000_state *state, u16 reg, #define dib9000_write16_noinc_attr(state, reg, buf, len, attribute) dib9000_write16_attr(state, reg, buf, len, DATA_BUS_ACCESS_MODE_NO_ADDRESS_INCREMENT | (attribute)) #define dib9000_mbx_send(state, id, data, len) dib9000_mbx_send_attr(state, id, data, len, 0) -#define dib9000_mbx_get_message(state, id, msg, len) dib9000_mbx_get_message_attr(state, id, msg, len, 0) +#define dib9000_mbx_get_message(state, id, msg, len, words) dib9000_mbx_get_message_attr(state, id, msg, len, words, 0) #define MAC_IRQ (1 << 1) #define IRQ_POL_MSK (1 << 4) @@ -725,7 +725,7 @@ static int dib9000_mbx_process(struct dib9000_state *state, u16 attr) return ret; } -static int dib9000_mbx_get_message_attr(struct dib9000_state *state, u16 id, u16 * msg, u8 * size, u16 attr) +static int dib9000_mbx_get_message_attr(struct dib9000_state *state, u16 id, u16 *msg, u8 *size, u16 msg_words, u16 attr) { u8 i; u16 *block; @@ -738,6 +738,10 @@ static int dib9000_mbx_get_message_attr(struct dib9000_state *state, u16 id, u16 block = state->platform.risc.message_cache[i]; if ((*block >> 8) == id) { *size = (*block & 0xff) - 1; + if (*size > msg_words) { + *block = 0; + return -1; + } memcpy(msg, block + 1, (*size) * 2); *block = 0; /* free the block */ i = 0; /* signal that we found a message */ @@ -770,7 +774,7 @@ static int dib9000_risc_check_version(struct dib9000_state *state) if (dib9000_mbx_send(state, OUT_MSG_REQ_VERSION, &fw_version, 1) != 0) return -EIO; - if (dib9000_mbx_get_message(state, IN_MSG_VERSION, (u16 *) r, &size) < 0) + if (dib9000_mbx_get_message(state, IN_MSG_VERSION, (u16 *) r, &size, sizeof(r) / sizeof(u16)) < 0) return -EIO; fw_version = (r[0] << 8) | r[1]; @@ -1022,7 +1026,7 @@ static int dib9000_risc_apb_access_read(struct dib9000_state *state, u32 address mb[0] = (u16) address; mb[1] = len / 2; dib9000_mbx_send_attr(state, OUT_MSG_BRIDGE_APB_R, mb, 2, attribute); - switch (dib9000_mbx_get_message_attr(state, IN_MSG_END_BRIDGE_APB_RW, mb, &s, attribute)) { + switch (dib9000_mbx_get_message_attr(state, IN_MSG_END_BRIDGE_APB_RW, mb, &s, ARRAY_SIZE(mb), attribute)) { case 1: s--; for (i = 0; i < s; i++) { @@ -1056,7 +1060,7 @@ static int dib9000_risc_apb_access_write(struct dib9000_state *state, u32 addres mb[1 + len / 2] = b[len - 1] << 8; dib9000_mbx_send_attr(state, OUT_MSG_BRIDGE_APB_W, mb, (3 + len) / 2, attribute); - return dib9000_mbx_get_message_attr(state, IN_MSG_END_BRIDGE_APB_RW, mb, &s, attribute) == 1 ? 0 : -EINVAL; + return dib9000_mbx_get_message_attr(state, IN_MSG_END_BRIDGE_APB_RW, mb, &s, ARRAY_SIZE(mb), attribute) == 1 ? 0 : -EINVAL; } static int dib9000_fw_memmbx_sync(struct dib9000_state *state, u8 i) @@ -1135,7 +1139,7 @@ static int dib9000_fw_init(struct dib9000_state *state) if (dib9000_mbx_send(state, OUT_MSG_FE_FW_DL, NULL, 0) != 0) return -EIO; - if (dib9000_mbx_get_message(state, IN_MSG_FE_FW_DL_DONE, b, &size) < 0) + if (dib9000_mbx_get_message(state, IN_MSG_FE_FW_DL_DONE, b, &size, ARRAY_SIZE(b)) < 0) return -EIO; if (size > ARRAY_SIZE(b)) { -- 2.34.1