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From: Adhemerval Zanella <azanella@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/azanella/ld-audit-fixes] elf: Add _dl_audit_pltenter Date: Wed, 4 Aug 2021 17:47:49 +0000 (GMT) [thread overview] Message-ID: <20210804174749.2F477386482B@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ae04d52d4a7c50ca280ce087e7c582fa16e4ba1c commit ae04d52d4a7c50ca280ce087e7c582fa16e4ba1c Author: Adhemerval Zanella <adhemerval.zanella@linaro.org> Date: Thu Jul 22 17:45:33 2021 -0300 elf: Add _dl_audit_pltenter It consolidates the code required to call la_pltenter() audit callback. Diff: --- elf/dl-audit.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++ elf/dl-runtime.c | 73 +------------------------------------------ sysdeps/generic/ldsodefs.h | 3 ++ 3 files changed, 81 insertions(+), 72 deletions(-) diff --git a/elf/dl-audit.c b/elf/dl-audit.c index a968cbde16..7d410bc128 100644 --- a/elf/dl-audit.c +++ b/elf/dl-audit.c @@ -17,7 +17,9 @@ <https://www.gnu.org/licenses/>. */ #include <assert.h> +#include <link.h> #include <ldsodefs.h> +#include <dl-machine.h> #ifdef SHARED void @@ -257,4 +259,79 @@ _dl_audit_symbind (struct link_map *l, struct reloc_result *reloc_result, reloc_result->flags = flags; *value = DL_FIXUP_ADDR_VALUE (sym.st_value); } + +void +_dl_audit_pltenter (struct link_map *l, struct reloc_result *reloc_result, + DL_FIXUP_VALUE_TYPE *value, void *regs, long int *framesize) +{ + /* Don't do anything if no auditor wants to intercept this call. */ + if (GLRO(dl_naudit) == 0 + || (reloc_result->enterexit & LA_SYMB_NOPLTENTER)) + return; + + /* Sanity check: DL_FIXUP_VALUE_CODE_ADDR (value) should have been + initialized earlier in this function or in another thread. */ + assert (DL_FIXUP_VALUE_CODE_ADDR (*value) != 0); + ElfW(Sym) *defsym = ((ElfW(Sym) *) D_PTR (reloc_result->bound, + l_info[DT_SYMTAB]) + + reloc_result->boundndx); + + /* Set up the sym parameter. */ + ElfW(Sym) sym = *defsym; + sym.st_value = DL_FIXUP_VALUE_ADDR (*value); + + /* Get the symbol name. */ + const char *strtab = (const void *) D_PTR (reloc_result->bound, + l_info[DT_STRTAB]); + const char *symname = strtab + sym.st_name; + + /* Keep track of overwritten addresses. */ + unsigned int flags = reloc_result->flags; + + struct audit_ifaces *afct = GLRO(dl_audit); + for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) + { + if (afct->ARCH_LA_PLTENTER != NULL + && (reloc_result->enterexit + & (LA_SYMB_NOPLTENTER << (2 * (cnt + 1)))) == 0) + { + long int new_framesize = -1; + struct auditstate *l_state = link_map_audit_state (l, cnt); + struct auditstate *bound_state + = link_map_audit_state (reloc_result->bound, cnt); + uintptr_t new_value + = afct->ARCH_LA_PLTENTER (&sym, reloc_result->boundndx, + &l_state->cookie, &bound_state->cookie, + regs, &flags, symname, &new_framesize); + if (new_value != (uintptr_t) sym.st_value) + { + flags |= LA_SYMB_ALTVALUE; + sym.st_value = new_value; + } + + /* Remember the results for every audit library and store a summary + in the first two bits. */ + reloc_result->enterexit |= ((flags & (LA_SYMB_NOPLTENTER + | LA_SYMB_NOPLTEXIT)) + << (2 * (cnt + 1))); + + if ((reloc_result->enterexit & (LA_SYMB_NOPLTEXIT + << (2 * (cnt + 1)))) + == 0 && new_framesize != -1 && *framesize != -2) + { + /* If this is the first call providing information, use it. */ + if (*framesize == -1) + *framesize = new_framesize; + /* If two pltenter calls provide conflicting information, use + the larger value. */ + else if (new_framesize != *framesize) + *framesize = MAX (new_framesize, *framesize); + } + } + + afct = afct->next; + } + + *value = DL_FIXUP_ADDR_VALUE (sym.st_value); +} #endif diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c index 680e66a6d6..4d16957c08 100644 --- a/elf/dl-runtime.c +++ b/elf/dl-runtime.c @@ -351,78 +351,7 @@ _dl_profile_fixup ( #ifdef SHARED /* Auditing checkpoint: report the PLT entering and allow the auditors to change the value. */ - if (GLRO(dl_naudit) > 0 - /* Don't do anything if no auditor wants to intercept this call. */ - && (reloc_result->enterexit & LA_SYMB_NOPLTENTER) == 0) - { - /* Sanity check: DL_FIXUP_VALUE_CODE_ADDR (value) should have been - initialized earlier in this function or in another thread. */ - assert (DL_FIXUP_VALUE_CODE_ADDR (value) != 0); - ElfW(Sym) *defsym = ((ElfW(Sym) *) D_PTR (reloc_result->bound, - l_info[DT_SYMTAB]) - + reloc_result->boundndx); - - /* Set up the sym parameter. */ - ElfW(Sym) sym = *defsym; - sym.st_value = DL_FIXUP_VALUE_ADDR (value); - - /* Get the symbol name. */ - const char *strtab = (const void *) D_PTR (reloc_result->bound, - l_info[DT_STRTAB]); - const char *symname = strtab + sym.st_name; - - /* Keep track of overwritten addresses. */ - unsigned int flags = reloc_result->flags; - - struct audit_ifaces *afct = GLRO(dl_audit); - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - if (afct->ARCH_LA_PLTENTER != NULL - && (reloc_result->enterexit - & (LA_SYMB_NOPLTENTER << (2 * (cnt + 1)))) == 0) - { - long int new_framesize = -1; - struct auditstate *l_state = link_map_audit_state (l, cnt); - struct auditstate *bound_state - = link_map_audit_state (reloc_result->bound, cnt); - uintptr_t new_value - = afct->ARCH_LA_PLTENTER (&sym, reloc_result->boundndx, - &l_state->cookie, - &bound_state->cookie, - regs, &flags, symname, - &new_framesize); - if (new_value != (uintptr_t) sym.st_value) - { - flags |= LA_SYMB_ALTVALUE; - sym.st_value = new_value; - } - - /* Remember the results for every audit library and - store a summary in the first two bits. */ - reloc_result->enterexit - |= ((flags & (LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT)) - << (2 * (cnt + 1))); - - if ((reloc_result->enterexit & (LA_SYMB_NOPLTEXIT - << (2 * (cnt + 1)))) - == 0 && new_framesize != -1 && framesize != -2) - { - /* If this is the first call providing information, - use it. */ - if (framesize == -1) - framesize = new_framesize; - /* If two pltenter calls provide conflicting information, - use the larger value. */ - else if (new_framesize != framesize) - framesize = MAX (new_framesize, framesize); - } - } - - afct = afct->next; - } - - value = DL_FIXUP_ADDR_VALUE (sym.st_value); - } + _dl_audit_pltenter (l, reloc_result, &value, regs, &framesize); #endif /* Store the frame size information. */ diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index 8eb4061a69..515ac5011b 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -1368,6 +1368,9 @@ void _dl_audit_symbind (struct link_map *l, struct reloc_result *reloc_result, void _dl_audit_symbind_alt (struct link_map *l, const ElfW(Sym) *ref, void **value, lookup_t result); rtld_hidden_proto (_dl_audit_symbind_alt) +void _dl_audit_pltenter (struct link_map *l, struct reloc_result *reloc_result, + DL_FIXUP_VALUE_TYPE *value, void *regs, + long int *framesize); #endif /* SHARED */ #if PTHREAD_IN_LIBC && defined SHARED
next reply other threads:[~2021-08-04 17:47 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-04 17:47 Adhemerval Zanella [this message] -- strict thread matches above, loose matches on Subject: below -- 2021-11-16 13:57 Adhemerval Zanella 2021-11-09 18:19 Adhemerval Zanella 2021-09-10 18:26 Adhemerval Zanella 2021-08-04 20:53 Adhemerval Zanella 2021-07-30 19:25 Adhemerval Zanella
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