diff options
Diffstat (limited to 'elf/dl-audit.c')
| -rw-r--r-- | elf/dl-audit.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/elf/dl-audit.c b/elf/dl-audit.c index 0b6fac8..15250c6 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> void _dl_audit_activity_map (struct link_map *l, int action) @@ -243,3 +245,78 @@ _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); +} |