Author: emaste Date: Sun Sep 1 16:12:05 2019 New Revision: 351659 URL: https://svnweb.freebsd.org/changeset/base/351659
Log: libc: remove gets gets is unsafe and shouldn't be used (for many years now). Leave it in the existing symbol version so anything that previously linked aginst it still runs, but do not allow new software to link against it. (The compatability/legacy implementation must not be static so that the symbol and in particular the compat sym gets@FBSD_1.0 make it into libc.) PR: 222796 (exp-run) Reported by: Paul Vixie Reviewed by: allanjude, cy, eadler, gnn, jhb, kib, ngie (some earlier) Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D12298 Modified: head/contrib/libc++/include/cstdio head/contrib/netbsd-tests/lib/libc/ssp/h_gets.c head/gnu/lib/libssp/Makefile head/include/stdio.h head/lib/libc/stdio/fgets.3 head/lib/libc/stdio/gets.c head/lib/libc/stdio/stdio.3 Modified: head/contrib/libc++/include/cstdio ============================================================================== --- head/contrib/libc++/include/cstdio Sun Sep 1 15:39:28 2019 (r351658) +++ head/contrib/libc++/include/cstdio Sun Sep 1 16:12:05 2019 (r351659) @@ -74,7 +74,6 @@ int fputc(int c, FILE* stream); int fputs(const char* restrict s, FILE* restrict stream); int getc(FILE* stream); int getchar(void); -char* gets(char* s); // removed in C++14 int putc(int c, FILE* stream); int putchar(int c); int puts(const char* s); @@ -153,9 +152,6 @@ using ::tmpnam; #ifndef _LIBCPP_HAS_NO_STDIN using ::getchar; -#if _LIBCPP_STD_VER <= 11 && !defined(_LIBCPP_MSVCRT) -using ::gets; -#endif using ::scanf; using ::vscanf; #endif Modified: head/contrib/netbsd-tests/lib/libc/ssp/h_gets.c ============================================================================== --- head/contrib/netbsd-tests/lib/libc/ssp/h_gets.c Sun Sep 1 15:39:28 2019 (r351658) +++ head/contrib/netbsd-tests/lib/libc/ssp/h_gets.c Sun Sep 1 16:12:05 2019 (r351659) @@ -33,6 +33,24 @@ __RCSID("$NetBSD: h_gets.c,v 1.1 2010/12/27 02:04:19 p #include <stdio.h> +#ifdef __FreeBSD__ +/* + * We want to test the gets() implementation, but cannot simply link against + * the gets symbol because it is not in the default version. (We've made it + * unavailable by default on FreeBSD because it should not be used.) + * + * The next two lines create an unsafe_gets() function that resolves to + * gets@FBSD_1.0, which we call from our local gets() implementation. + */ +__sym_compat(gets, unsafe_gets, FBSD_1.0); +char *unsafe_gets(char *); + +char *gets(char *buf) +{ + return unsafe_gets(buf); +} +#endif + int main(int argc, char *argv[]) { Modified: head/gnu/lib/libssp/Makefile ============================================================================== --- head/gnu/lib/libssp/Makefile Sun Sep 1 15:39:28 2019 (r351658) +++ head/gnu/lib/libssp/Makefile Sun Sep 1 16:12:05 2019 (r351659) @@ -17,7 +17,7 @@ LIB= ssp SHLIB_MAJOR= 0 LD_FATAL_WARNINGS= no -SRCS= ssp.c gets-chk.c memcpy-chk.c memmove-chk.c mempcpy-chk.c \ +SRCS= ssp.c memcpy-chk.c memmove-chk.c mempcpy-chk.c \ memset-chk.c snprintf-chk.c sprintf-chk.c stpcpy-chk.c \ strcat-chk.c strcpy-chk.c strncat-chk.c strncpy-chk.c \ vsnprintf-chk.c vsprintf-chk.c Modified: head/include/stdio.h ============================================================================== --- head/include/stdio.h Sun Sep 1 15:39:28 2019 (r351658) +++ head/include/stdio.h Sun Sep 1 16:12:05 2019 (r351659) @@ -269,7 +269,6 @@ long ftell(FILE *); size_t fwrite(const void * __restrict, size_t, size_t, FILE * __restrict); int getc(FILE *); int getchar(void); -char *gets(char *); #if __EXT1_VISIBLE char *gets_s(char *, rsize_t); #endif Modified: head/lib/libc/stdio/fgets.3 ============================================================================== --- head/lib/libc/stdio/fgets.3 Sun Sep 1 15:39:28 2019 (r351658) +++ head/lib/libc/stdio/fgets.3 Sun Sep 1 16:12:05 2019 (r351659) @@ -32,12 +32,11 @@ .\" @(#)fgets.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD$ .\" -.Dd April 3, 2018 +.Dd September 1, 2019 .Dt FGETS 3 .Os .Sh NAME .Nm fgets , -.Nm gets , .Nm gets_s .Nd get a line from a stream .Sh LIBRARY @@ -48,8 +47,6 @@ .Fn fgets "char * restrict str" "int size" "FILE * restrict stream" .Ft char * .Fn gets_s "char *str" "rsize_t size" -.Ft char * -.Fn gets "char *str" .Sh DESCRIPTION The .Fn fgets @@ -81,23 +78,12 @@ except that the newline character (if any) is not stor The .Fn gets function -is equivalent to -.Fn fgets -with an infinite -.Fa size -and a -.Fa stream -of -.Dv stdin , -except that the newline character (if any) is not stored in the string. -It is the caller's responsibility to ensure that the input line, -if any, is sufficiently short to fit in the string. +was unsafe and is no longer available. .Sh RETURN VALUES Upon successful completion, -.Fn fgets , -.Fn gets_s , +.Fn fgets and -.Fn gets +.Fn gets_s return a pointer to the string. If end-of-file occurs before any characters are read, @@ -109,10 +95,9 @@ they return .Dv NULL and the buffer contents are indeterminate. The -.Fn fgets , -.Fn gets_s , +.Fn fgets and -.Fn gets +.Fn gets_s functions do not distinguish between end-of-file and error, and callers must use .Xr feof 3 @@ -139,8 +124,6 @@ or .Xr malloc 3 . .Pp The function -.Fn gets -and .Fn gets_s may also fail and set .Va errno @@ -153,11 +136,9 @@ for any of the errors specified for the routine .Xr fgetws 3 , .Xr getline 3 .Sh STANDARDS -The functions +The .Fn fgets -and -.Fn gets -conform to +function conforms to .St -isoC-99 . .Fn gets_s conforms to @@ -166,16 +147,3 @@ K.3.7.4.1. .Fn gets has been removed from .St -isoC-2011 . -.Sh SECURITY CONSIDERATIONS -The -.Fn gets -function cannot be used securely. -Because of its lack of bounds checking, -and the inability for the calling program -to reliably determine the length of the next incoming line, -the use of this function enables malicious users -to arbitrarily change a running program's functionality through -a buffer overflow attack. -It is strongly suggested that the -.Fn fgets -function be used in all cases. Modified: head/lib/libc/stdio/gets.c ============================================================================== --- head/lib/libc/stdio/gets.c Sun Sep 1 15:39:28 2019 (r351658) +++ head/lib/libc/stdio/gets.c Sun Sep 1 16:12:05 2019 (r351659) @@ -45,10 +45,8 @@ __FBSDID("$FreeBSD$"); #include "libc_private.h" #include "local.h" -__warn_references(gets, "warning: this program uses gets(), which is unsafe."); - char * -gets(char *buf) +__gets_unsafe(char *buf) { int c; char *s, *ret; @@ -78,3 +76,4 @@ end: FUNLOCKFILE_CANCELSAFE(); return (ret); } +__sym_compat(gets, __gets_unsafe, FBSD_1.0); Modified: head/lib/libc/stdio/stdio.3 ============================================================================== --- head/lib/libc/stdio/stdio.3 Sun Sep 1 15:39:28 2019 (r351658) +++ head/lib/libc/stdio/stdio.3 Sun Sep 1 16:12:05 2019 (r351659) @@ -279,7 +279,6 @@ library conforms to .It "getchar get next character or word from input stream" .It "getdelim get a line from a stream" .It "getline get a line from a stream" -.It "gets get a line from a stream" .It "getw get next character or word from input stream" .It "getwc get next wide character from input stream" .It "getwchar get next wide character from input stream" _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"