From ff917923f4fb9c83717ba135ee47d7e4c1567bb7 Mon Sep 17 00:00:00 2001 From: Muhammad Bilal Date: Tue, 28 Jul 2026 17:54:55 +0500 Subject: staging: rtl8723bs: fix OOB read in rtw_action_frame_parse() rtw_action_frame_parse() takes a frame_len parameter but never actually checks it before indexing into the frame body: const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr); ... c = frame_body[0]; ... a = frame_body[1]; frame_body already points 24 bytes (sizeof(struct ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and frame_body[1] requires frame_len >= 26. A management action frame shorter than that (e.g. exactly 24 bytes, the minimum a malicious peer can send) causes a 1-2 byte out-of-bounds read. This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass attacker/user-influenced frame buffers and lengths straight through. Add the missing length check before frame_body is dereferenced. Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com Signed-off-by: Greg Kroah-Hartman --- arch/riscv/lib/strcmp.S | 125 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 arch/riscv/lib/strcmp.S (limited to 'arch/riscv/lib/strcmp.S') diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S new file mode 100644 index 000000000..65027e742 --- /dev/null +++ b/arch/riscv/lib/strcmp.S @@ -0,0 +1,125 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include +#include +#include +#include + +/* int strcmp(const char *cs, const char *ct) */ +SYM_FUNC_START(strcmp) + + __ALTERNATIVE_CFG("nop", "j strcmp_zbb", 0, RISCV_ISA_EXT_ZBB, + IS_ENABLED(CONFIG_RISCV_ISA_ZBB) && IS_ENABLED(CONFIG_TOOLCHAIN_HAS_ZBB)) + + /* + * Returns + * a0 - comparison result, value like strcmp + * + * Parameters + * a0 - string1 + * a1 - string2 + * + * Clobbers + * t0, t1 + */ +1: + lbu t0, 0(a0) + lbu t1, 0(a1) + addi a0, a0, 1 + addi a1, a1, 1 + bne t0, t1, 2f + bnez t0, 1b + li a0, 0 + ret +2: + /* + * strcmp only needs to return (< 0, 0, > 0) values + * not necessarily -1, 0, +1 + */ + sub a0, t0, t1 + ret + +/* + * Variant of strcmp using the ZBB extension if available. + * The code was published as part of the bitmanip manual + * in Appendix A. + */ +#if defined(CONFIG_RISCV_ISA_ZBB) && defined(CONFIG_TOOLCHAIN_HAS_ZBB) +strcmp_zbb: + +.option push +.option arch,+zbb + + /* + * Returns + * a0 - comparison result, value like strcmp + * + * Parameters + * a0 - string1 + * a1 - string2 + * + * Clobbers + * t0, t1, t2, t3, t4 + */ + + or t2, a0, a1 + li t4, -1 + and t2, t2, SZREG-1 + bnez t2, 3f + + /* Main loop for aligned string. */ + .p2align 3 +1: + REG_L t0, 0(a0) + REG_L t1, 0(a1) + orc.b t3, t0 + bne t3, t4, 2f + addi a0, a0, SZREG + addi a1, a1, SZREG + beq t0, t1, 1b + + /* + * Words don't match, and no null byte in the first + * word. Get bytes in big-endian order and compare. + */ +#ifndef CONFIG_CPU_BIG_ENDIAN + rev8 t0, t0 + rev8 t1, t1 +#endif + + /* Synthesize (t0 >= t1) ? 1 : -1 in a branchless sequence. */ + sltu a0, t0, t1 + neg a0, a0 + ori a0, a0, 1 + ret + +2: + /* + * Found a null byte. + * If words don't match, fall back to simple loop. + */ + bne t0, t1, 3f + + /* Otherwise, strings are equal. */ + li a0, 0 + ret + + /* Simple loop for misaligned strings. */ + .p2align 3 +3: + lbu t0, 0(a0) + lbu t1, 0(a1) + addi a0, a0, 1 + addi a1, a1, 1 + bne t0, t1, 4f + bnez t0, 3b + +4: + sub a0, t0, t1 + ret + +.option pop +#endif +SYM_FUNC_END(strcmp) +SYM_FUNC_ALIAS(__pi_strcmp, strcmp) +EXPORT_SYMBOL(strcmp) -- cgit v1.3.1