MIPS: Module: Deal with malformed HI16/LO16 relocation sequences.
In case a series of R_MIPS_HI16 relocations was not followed by an R_MIPS_LO16 relocation we were leaking the hi16 relocation chain. Handle that error and return an error. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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@ -140,19 +140,30 @@ static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
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return 0;
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}
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static void free_relocation_chain(struct mips_hi16 *l)
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{
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struct mips_hi16 *next;
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while (l) {
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next = l->next;
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kfree(l);
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l = next;
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}
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}
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static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
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{
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unsigned long insnlo = *location;
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struct mips_hi16 *l;
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Elf_Addr val, vallo;
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struct mips_hi16 *l, *next;
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/* Sign extend the addend we extract from the lo insn. */
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vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
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if (me->arch.r_mips_hi16_list != NULL) {
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l = me->arch.r_mips_hi16_list;
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while (l != NULL) {
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struct mips_hi16 *next;
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unsigned long insn;
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/*
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@ -198,11 +209,8 @@ static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
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return 0;
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out_danger:
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while (l) {
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next = l->next;
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kfree(l);
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l = next;
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}
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free_relocation_chain(l);
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me->arch.r_mips_hi16_list = NULL;
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pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name);
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@ -300,6 +308,19 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
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return res;
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}
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/*
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* Normally the hi16 list should be deallocated at this point. A
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* malformed binary however could contain a series of R_MIPS_HI16
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* relocations not followed by a R_MIPS_LO16 relocation. In that
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* case, free up the list and return an error.
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*/
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if (me->arch.r_mips_hi16_list) {
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free_relocation_chain(me->arch.r_mips_hi16_list);
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me->arch.r_mips_hi16_list = NULL;
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return -ENOEXEC;
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}
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return 0;
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}
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