Date: Fri, 23 Oct 2009 19:07:31 GMT From: Jonathan Anderson <jona@FreeBSD.org> To: Perforce Change Reviews <perforce@FreeBSD.org> Subject: PERFORCE change 169737 for review Message-ID: <200910231907.n9NJ7VCb051605@repoman.freebsd.org>
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http://p4web.freebsd.org/chv.cgi?CH=169737 Change 169737 by jona@jona-capsicum-kent on 2009/10/23 19:07:18 Add a _capstart() to crt.o which calls the [weak symbol] cap_main(); this fixes the problem where rtld on amd64 gets the stack wrong when entering cap_main() Affected files ... .. //depot/projects/trustedbsd/capabilities/TODO#14 edit .. //depot/projects/trustedbsd/capabilities/src/lib/csu/amd64/crt1.c#2 edit .. //depot/projects/trustedbsd/capabilities/src/lib/csu/common/crtbrand.c#2 edit .. //depot/projects/trustedbsd/capabilities/src/lib/csu/i386-elf/crt1.c#2 edit .. //depot/projects/trustedbsd/capabilities/src/libexec/rtld-elf/rtld.c#29 edit Differences ... ==== //depot/projects/trustedbsd/capabilities/TODO#14 (text+ko) ==== @@ -55,3 +55,7 @@ - Enable capability mode system calls in compat32. Add compat system call parts for new system calls. + +- Add support (a.k.a. find test platforms) for arm, ia64, etc. in lib/csu + +- It would be nice if we didn't need -rdynamic; can we export just _capstart? Should we add more information (a capability entry point) to ELF? ==== //depot/projects/trustedbsd/capabilities/src/lib/csu/amd64/crt1.c#2 (text+ko) ==== @@ -43,7 +43,9 @@ extern void _fini(void); extern void _init(void); extern int main(int, char **, char **); +extern int cap_main(int, char **, char **) __attribute__((weak)); extern void _start(char **, void (*)(void)); +extern void _capstart(char **, void (*)(void)); #ifdef GCRT extern void _mcleanup(void); @@ -92,4 +94,42 @@ exit( main(argc, argv, env) ); } + +/* The Capsicum entry function. */ +void +_capstart(char **ap, void (*cleanup)(void)) +{ + int argc; + char **argv; + char **env; + const char *s; + + argc = *(long *)(void *)ap; + argv = ap + 1; + env = ap + 2 + argc; + environ = env; + if (argc > 0 && argv[0] != NULL) { + __progname = argv[0]; + for (s = __progname; *s != '\0'; s++) + if (*s == '/') + __progname = s + 1; + } + + if (&_DYNAMIC != NULL) + atexit(cleanup); + else + _init_tls(); + +#ifdef GCRT + atexit(_mcleanup); +#endif + atexit(_fini); +#ifdef GCRT +/* monstartup(&eprol, &etext); +__asm__("eprol:");*/ /* XXX: does this interfere with profiling? */ +#endif + _init(); + exit( cap_main(argc, argv, env) ); +} + __asm__(".ident\t\"$FreeBSD: src/lib/csu/amd64/crt1.c,v 1.15 2005/10/07 22:13:17 bde Exp $\""); ==== //depot/projects/trustedbsd/capabilities/src/lib/csu/common/crtbrand.c#2 (text+ko) ==== @@ -27,6 +27,7 @@ __FBSDID("$FreeBSD: src/lib/csu/common/crtbrand.c,v 1.6 2007/12/04 12:18:43 kib Exp $"); #include <sys/param.h> +#include <unistd.h> #define ABI_VENDOR "FreeBSD" #define ABI_SECTION ".note.ABI-tag" @@ -50,3 +51,12 @@ ABI_VENDOR, __FreeBSD_version }; + +int cap_main(int argc, char **argv, char **env) +{ + const char warning[] = + "ERROR: attempting to run a regular binary in capability mode.\n\nIf you wish to run a binary in a sandbox, you must provide a cap_main() function which takes the same arguments as main().\n"; + + write(2, warning, sizeof(warning)); +} + ==== //depot/projects/trustedbsd/capabilities/src/lib/csu/i386-elf/crt1.c#2 (text+ko) ==== @@ -43,7 +43,9 @@ extern void _fini(void); extern void _init(void); extern int main(int, char **, char **); +extern int cap_main(int, char **, char **) __attribute__((weak)); extern void _start(char *, ...); +extern void _capstart(char *, ...); #ifdef GCRT extern void _mcleanup(void); @@ -110,4 +112,47 @@ exit( main(argc, argv, env) ); } + +/* The Capsicum entry function. */ +void +_capstart(char *ap, ...) +{ + fptr cleanup; + int argc; + char **argv; + char **env; + const char *s; + +#ifdef __GNUC__ + __asm__("and $0xfffffff0,%esp"); +#endif + cleanup = get_rtld_cleanup(); + argv = ≈ + argc = *(long *)(void *)(argv - 1); + env = argv + argc + 1; + environ = env; + if (argc > 0 && argv[0] != NULL) { + __progname = argv[0]; + for (s = __progname; *s != '\0'; s++) + if (*s == '/') + __progname = s + 1; + } + + if (&_DYNAMIC != NULL) + atexit(cleanup); + else + _init_tls(); + +#ifdef GCRT + atexit(_mcleanup); +#endif + atexit(_fini); +#ifdef GCRT +/* monstartup(&eprol, &etext); +__asm__("eprol:");*/ /* XXX: does this interfere with profiling? */ +#endif + _init(); + exit( cap_main(argc, argv, env) ); +} + __asm__(".ident\t\"$FreeBSD: src/lib/csu/i386-elf/crt1.c,v 1.15 2005/10/07 22:13:17 bde Exp $\""); ==== //depot/projects/trustedbsd/capabilities/src/libexec/rtld-elf/rtld.c#29 (text+ko) ==== @@ -106,7 +106,7 @@ static void errmsg_restore(char *); static char *errmsg_save(void); #ifdef IN_RTLD_CAP -static void *find_cap_main(const Obj_Entry *); +static void *find_capstart(const Obj_Entry *); #else static void *fill_search_info(const char *, size_t, void *); static char *find_library(const char *, const Obj_Entry *); @@ -348,7 +348,7 @@ #ifdef IN_RTLD_CAP struct stat sb; Elf_Auxinfo aux_execfd; - void *cap_main_ptr; + void *capstart_ptr; #endif Elf_Auxinfo *aux_info[AT_COUNT]; int i; @@ -650,12 +650,12 @@ * point, prefer that to the ELF default entry point. Otherwise, use the * ELF default. */ - cap_main_ptr = find_cap_main(obj_main); - if (cap_main_ptr == NULL) { - _rtld_error("cap_main not found"); + capstart_ptr = find_capstart(obj_main); + if (capstart_ptr == NULL) { + _rtld_error("_capstart not found; has the binary been compiled with -rdynamic?"); die(); } - return (func_ptr_type) cap_main_ptr; + return (func_ptr_type) capstart_ptr; #else return (func_ptr_type) obj_main->entry; #endif @@ -827,15 +827,15 @@ #ifdef IN_RTLD_CAP static void * -find_cap_main(const Obj_Entry *obj) +find_capstart(const Obj_Entry *obj) { - const char *cap_main_str = "cap_main"; + const char *capstart_str = "_capstart"; const Elf_Sym *def; const Obj_Entry *defobj; unsigned long hash; - hash = elf_hash(cap_main_str); - def = symlook_default(cap_main_str, hash, obj, &defobj, NULL, + hash = elf_hash(capstart_str); + def = symlook_default(capstart_str, hash, obj, &defobj, NULL, SYMLOOK_IN_PLT); if (def == NULL) return (NULL);
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