From 505c884aeb059ee7741c23d1bfc47956bd9c2a0e Mon Sep 17 00:00:00 2001 From: Frédéric Bérat Date: Wed, 26 Apr 2023 17:26:51 +0200 Subject: stdio: Ensure *_chk routines have their hidden builtin definition available If libc_hidden_builtin_{def,proto} isn't properly set for *_chk routines, there are unwanted PLT entries in libc.so. There is a special case with __asprintf_chk: If ldbl_* macros are used for asprintf, ABI gets broken on s390x, if it isn't, ppc64le isn't building due to multiple asm redirections. This is due to the inclusion of bits/stdio-lbdl.h for ppc64le whereas it isn't for s390x. This header creates redirections, which are not compatible with the ones generated using libc_hidden_def. Yet, we can't use libc_hidden_ldbl_proto on s390x since it will not create a simple strong alias (e.g. as done on x86_64), but a versioned alias, leading to ABI breakage. This results in errors on s390x: /usr/bin/ld: glibc/iconv/../libio/bits/stdio2.h:137: undefined reference to `__asprintf_chk' Original __asprintf_chk symbols: 00000000001395b0 T __asprintf_chk 0000000000177e90 T __nldbl___asprintf_chk __asprintf_chk symbols with ldbl_* macros: 000000000012d590 t ___asprintf_chk 000000000012d590 t __asprintf_chk@@GLIBC_2.4 000000000012d590 t __GI___asprintf_chk 000000000012d590 t __GL____asprintf_chk___asprintf_chk 0000000000172240 T __nldbl___asprintf_chk __asprintf_chk symbols with the patch: 000000000012d590 t ___asprintf_chk 000000000012d590 T __asprintf_chk 000000000012d590 t __GI___asprintf_chk 0000000000172240 T __nldbl___asprintf_chk Reviewed-by: Carlos O'Donell --- debug/asprintf_chk.c | 18 +++++++++++++++++- debug/fgets_u_chk.c | 1 + debug/fprintf_chk.c | 1 + debug/sprintf_chk.c | 1 + 4 files changed, 20 insertions(+), 1 deletion(-) (limited to 'debug') diff --git a/debug/asprintf_chk.c b/debug/asprintf_chk.c index 651c2cd76b..e233d5d737 100644 --- a/debug/asprintf_chk.c +++ b/debug/asprintf_chk.c @@ -22,7 +22,7 @@ /* Write formatted output from FORMAT to a string which is allocated with malloc and stored in *STRING_PTR. */ int -__asprintf_chk (char **result_ptr, int flag, const char *format, ...) +___asprintf_chk (char **result_ptr, int flag, const char *format, ...) { /* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n can only come from read-only format strings. */ @@ -36,3 +36,19 @@ __asprintf_chk (char **result_ptr, int flag, const char *format, ...) return ret; } +#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1 +/* This is needed since is included in this case, leading to + * multiple asm redirection of the same symbol + */ +ldbl_hidden_def (___asprintf_chk, __asprintf_chk) +ldbl_strong_alias (___asprintf_chk, __asprintf_chk) +#else +/* On some systems introduction of ldbl_* macros lead to ABI breakage due to the + * long_double_symbol aliasing, e.g. on s390x: + * /usr/bin/ld: glibc/iconv/../libio/bits/stdio2.h:137: undefined reference to + * `__asprintf_chk' + * Due to __asprintf_chk@@GLIBC_2.4 alias replacing __asprintf_chk. + */ +strong_alias (___asprintf_chk, __asprintf_chk) +libc_hidden_def (__asprintf_chk) +#endif diff --git a/debug/fgets_u_chk.c b/debug/fgets_u_chk.c index a16ba655e6..74275381f5 100644 --- a/debug/fgets_u_chk.c +++ b/debug/fgets_u_chk.c @@ -56,3 +56,4 @@ __fgets_unlocked_chk (char *buf, size_t size, int n, FILE *fp) fp->_flags |= old_error; return result; } +libc_hidden_builtin_def (__fgets_unlocked_chk) diff --git a/debug/fprintf_chk.c b/debug/fprintf_chk.c index b57d538d03..273051ef91 100644 --- a/debug/fprintf_chk.c +++ b/debug/fprintf_chk.c @@ -35,4 +35,5 @@ ___fprintf_chk (FILE *fp, int flag, const char *format, ...) return ret; } +ldbl_hidden_def (___fprintf_chk, __fprintf_chk) ldbl_strong_alias (___fprintf_chk, __fprintf_chk) diff --git a/debug/sprintf_chk.c b/debug/sprintf_chk.c index b27f4afae8..e45f1e7b3b 100644 --- a/debug/sprintf_chk.c +++ b/debug/sprintf_chk.c @@ -42,4 +42,5 @@ ___sprintf_chk (char *s, int flag, size_t slen, const char *format, ...) return ret; } +ldbl_hidden_def (___sprintf_chk, __sprintf_chk) ldbl_strong_alias (___sprintf_chk, __sprintf_chk) -- cgit 1.4.1