diff options
author | Sergei Trofimovich <slyfox@gentoo.org> | 2021-04-29 22:53:48 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-22 10:59:42 +0200 |
commit | 0f6a886753b4e1ff4bf1d38160c0915e35112771 (patch) | |
tree | 63df91becc28d9f01c36669e9f2bb0c5c161a2d3 /arch/ia64/kernel | |
parent | 65fecc2d3c1b5a5a8c31dca03d6623b3a0aab276 (diff) |
ia64: module: fix symbolizer crash on fdescr
[ Upstream commit 99e729bd40fb3272fa4b0140839d5e957b58588a ]
Noticed failure as a crash on ia64 when tried to symbolize all backtraces
collected by page_owner=on:
$ cat /sys/kernel/debug/page_owner
<oops>
CPU: 1 PID: 2074 Comm: cat Not tainted 5.12.0-rc4 #226
Hardware name: hp server rx3600, BIOS 04.03 04/08/2008
ip is at dereference_module_function_descriptor+0x41/0x100
Crash happens at dereference_module_function_descriptor() due to
use-after-free when dereferencing ".opd" section header.
All section headers are already freed after module is laoded successfully.
To keep symbolizer working the change stores ".opd" address and size after
module is relocated to a new place and before section headers are
discarded.
To make similar errors less obscure module_finalize() now zeroes out all
variables relevant to module loading only.
Link: https://lkml.kernel.org/r/20210403074803.3309096-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/ia64/kernel')
-rw-r--r-- | arch/ia64/kernel/module.c | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c index 1a42ba885188..ee693c8cec49 100644 --- a/arch/ia64/kernel/module.c +++ b/arch/ia64/kernel/module.c @@ -905,9 +905,31 @@ register_unwind_table (struct module *mod) int module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) { + struct mod_arch_specific *mas = &mod->arch; + DEBUGP("%s: init: entry=%p\n", __func__, mod->init); - if (mod->arch.unwind) + if (mas->unwind) register_unwind_table(mod); + + /* + * ".opd" was already relocated to the final destination. Store + * it's address for use in symbolizer. + */ + mas->opd_addr = (void *)mas->opd->sh_addr; + mas->opd_size = mas->opd->sh_size; + + /* + * Module relocation was already done at this point. Section + * headers are about to be deleted. Wipe out load-time context. + */ + mas->core_plt = NULL; + mas->init_plt = NULL; + mas->got = NULL; + mas->opd = NULL; + mas->unwind = NULL; + mas->gp = 0; + mas->next_got_entry = 0; + return 0; } @@ -926,10 +948,9 @@ module_arch_cleanup (struct module *mod) void *dereference_module_function_descriptor(struct module *mod, void *ptr) { - Elf64_Shdr *opd = mod->arch.opd; + struct mod_arch_specific *mas = &mod->arch; - if (ptr < (void *)opd->sh_addr || - ptr >= (void *)(opd->sh_addr + opd->sh_size)) + if (ptr < mas->opd_addr || ptr >= mas->opd_addr + mas->opd_size) return ptr; return dereference_function_descriptor(ptr); |