From 2037a739971da7bae49b86b6de5418ff9ea592f3 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Mon, 20 Nov 2023 14:22:22 +0100 Subject: [PATCH] disas/cris: Pass buffer size to format_dec() to avoid overflow warning MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Propagate the buffer size to format_dec() and use snprintf(). This should silence this UBSan -Wformat-overflow warning: In file included from /usr/include/stdio.h:906, from include/qemu/osdep.h:114, from ../disas/cris.c:21: In function 'sprintf', inlined from 'format_dec' at ../disas/cris.c:1737:3, inlined from 'print_with_operands' at ../disas/cris.c:2477:12, inlined from 'print_insn_cris_generic.constprop' at ../disas/cris.c:2690:8: /usr/include/bits/stdio2.h:30:10: warning: null destination pointer [-Wformat-overflow=] 30 | return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 31 | __glibc_objsize (__s), __fmt, | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 32 | __va_arg_pack ()); | ~~~~~~~~~~~~~~~~~ Reported-by: Akihiko Odaki Signed-off-by: Philippe Mathieu-Daudé Message-ID: <20231120132222.82138-1-philmd@linaro.org> [Rewritten to fix logic and avoid repeated expression. - Paolo] Signed-off-by: Paolo Bonzini --- disas/cris.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/disas/cris.c b/disas/cris.c index 0b0a3fb916..409a224c5d 100644 --- a/disas/cris.c +++ b/disas/cris.c @@ -1731,10 +1731,10 @@ format_hex (unsigned long number, unsigned (== 0). */ static char * -format_dec (long number, char *outbuffer, int signedp) +format_dec (long number, char *outbuffer, size_t outsize, int signedp) { last_immediate = number; - sprintf (outbuffer, signedp ? "%ld" : "%lu", number); + snprintf (outbuffer, outsize, signedp ? "%ld" : "%lu", number); return outbuffer + strlen (outbuffer); } @@ -1876,6 +1876,12 @@ print_flags (struct cris_disasm_data *disdata, unsigned int insn, char *cp) return cp; } +#define FORMAT_DEC(number, tp, signedp) \ + format_dec (number, tp, ({ \ + assert(tp >= temp && tp <= temp + sizeof(temp)); \ + temp + sizeof(temp) - tp; \ + }), signedp) + /* Print out an insn with its operands, and update the info->insn_type fields. The prefix_opcodep and the rest hold a prefix insn that is supposed to be output as an address mode. */ @@ -2105,7 +2111,7 @@ print_with_operands (const struct cris_opcode *opcodep, if ((*cs == 'z' && (insn & 0x20)) || (opcodep->match == BDAP_QUICK_OPCODE && (nbytes <= 2 || buffer[1 + nbytes] == 0))) - tp = format_dec (number, tp, signedp); + tp = FORMAT_DEC (number, tp, signedp); else { unsigned int highbyte = (number >> 24) & 0xff; @@ -2241,7 +2247,7 @@ print_with_operands (const struct cris_opcode *opcodep, with_reg_prefix); if (number >= 0) *tp++ = '+'; - tp = format_dec (number, tp, 1); + tp = FORMAT_DEC (number, tp, 1); info->flags |= CRIS_DIS_FLAG_MEM_TARGET_IS_REG; info->target = (prefix_insn >> 12) & 15; @@ -2340,7 +2346,7 @@ print_with_operands (const struct cris_opcode *opcodep, { if (number >= 0) *tp++ = '+'; - tp = format_dec (number, tp, 1); + tp = FORMAT_DEC (number, tp, 1); } } else @@ -2397,7 +2403,7 @@ print_with_operands (const struct cris_opcode *opcodep, break; case 'I': - tp = format_dec (insn & 63, tp, 0); + tp = FORMAT_DEC (insn & 63, tp, 0); break; case 'b': @@ -2426,11 +2432,11 @@ print_with_operands (const struct cris_opcode *opcodep, break; case 'c': - tp = format_dec (insn & 31, tp, 0); + tp = FORMAT_DEC (insn & 31, tp, 0); break; case 'C': - tp = format_dec (insn & 15, tp, 0); + tp = FORMAT_DEC (insn & 15, tp, 0); break; case 'o': @@ -2463,7 +2469,7 @@ print_with_operands (const struct cris_opcode *opcodep, if (number > 127) number = number - 256; - tp = format_dec (number, tp, 1); + tp = FORMAT_DEC (number, tp, 1); *tp++ = ','; tp = format_reg (disdata, (insn >> 12) & 15, tp, with_reg_prefix); } @@ -2474,7 +2480,7 @@ print_with_operands (const struct cris_opcode *opcodep, break; case 'i': - tp = format_dec ((insn & 32) ? (insn & 31) | ~31L : insn & 31, tp, 1); + tp = FORMAT_DEC ((insn & 32) ? (insn & 31) | ~31L : insn & 31, tp, 1); break; case 'P': -- 2.30.2