From: Alan Modra Date: Sun, 20 Apr 2025 23:33:52 +0000 (+0930) Subject: avoid bogus format-overflow error X-Git-Tag: binutils-2_45~858 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9c7ed7b7fdbe4e25b4bad5e64f5d37936e4c9045;p=thirdparty%2Fbinutils-gdb.git avoid bogus format-overflow error Seen on x86_64-linux Ubuntu 24.04.2 using gcc-13.3.0 with CFLAGS="-m32 -g -O2 -fsanitize=address,undefined" In function ‘sprintf’, inlined from ‘s_mri_for’ at gas/config/tc-m68k.c:6941:5: /usr/include/bits/stdio2.h:30:10: error: null destination pointer [-Werror=format-overflow=] 30 | return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 31 | __glibc_objsize (__s), __fmt, | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 32 | __va_arg_pack ()); | ~~~~~~~~~~~~~~~~~ Rewrite the code without sprintf, as in other parts of s_mri_for. See also commit 760fb390fd4c and following commits. Note that adding -D_FORTIFY_SOURCE=0 to CFLAGS (which is a good idea when building with sanitizers) merely transforms the sprintf_chk error here into one regarding plain sprintf. --- diff --git a/gas/config/tc-m68k.c b/gas/config/tc-m68k.c index 0f36741fec1..46b26d4f38a 100644 --- a/gas/config/tc-m68k.c +++ b/gas/config/tc-m68k.c @@ -6754,7 +6754,6 @@ s_mri_for (int qual) struct mri_control_info *n; char *buf; char *s; - char ex[2]; /* The syntax is FOR.q var = init { TO | DOWNTO } end [ BY by ] DO.e @@ -6935,12 +6934,14 @@ s_mri_for (int qual) mri_assemble (buf); /* bcc bottom. */ - ex[0] = TOLOWER (extent); - ex[1] = '\0'; - if (up) - sprintf (buf, "blt%s %s", ex, n->bottom); - else - sprintf (buf, "bgt%s %s", ex, n->bottom); + s = buf; + *s++ = 'b'; + *s++ = up ? 'l' : 'g'; + *s++ = 't'; + if (extent != '\0') + *s++ = TOLOWER (extent); + *s++ = ' '; + strcpy (s, n->bottom); mri_assemble (buf); /* Put together the add or sub instruction used by ENDF. */