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relocate a program interpreter to the map_start

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This commit makes a system call that dereferences a NULL pointer fail.
This commit is contained in:
NAKAMURA Gou
2014-01-14 15:23:15 +09:00
parent 6992b829a0
commit c421965542
4 changed files with 33 additions and 3 deletions
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7
executer/user/mcexec.c
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@ -248,6 +248,7 @@ struct program_load_desc *load_interp(struct program_load_desc *desc0, FILE *fp)
int i, j, nhdrs = 0;
struct program_load_desc *desc = desc0;
size_t newsize;
unsigned long align;
if (fread(&hdr, sizeof(hdr), 1, fp) < 1) {
__eprint("Cannot read Ehdr.\n");
@ -278,6 +279,7 @@ struct program_load_desc *load_interp(struct program_load_desc *desc0, FILE *fp)
}
fseek(fp, hdr.e_phoff, SEEK_SET);
align = 1;
j = desc->num_sections;
for (i = 0; i < hdr.e_phnum; i++) {
if (fread(&phdr, sizeof(phdr), 1, fp) < 1) {
@ -301,6 +303,10 @@ struct program_load_desc *load_interp(struct program_load_desc *desc0, FILE *fp)
desc->sections[j].prot |= (phdr.p_flags & PF_W)? PROT_WRITE: 0;
desc->sections[j].prot |= (phdr.p_flags & PF_X)? PROT_EXEC: 0;
if (phdr.p_align > align) {
align = phdr.p_align;
}
__dprintf("%d: (%s) %lx, %lx, %lx, %lx, %x\n",
j, (phdr.p_type == PT_LOAD ? "PT_LOAD" : "PT_TLS"),
desc->sections[j].vaddr,
@ -314,6 +320,7 @@ struct program_load_desc *load_interp(struct program_load_desc *desc0, FILE *fp)
desc->num_sections = j;
desc->entry = hdr.e_entry;
desc->interp_align = align;
return desc;
}