The patch titled
Subject: kernel/kexec_file.c: search symbols in read-only kexec_purgatory
has been added to the -mm tree. Its filename is
kexec_file-search-symbols-in-read-only-kexec_purgatory.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kexec_file-search-symbols-in-read-only-kexec_purgatory.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kexec_file-search-symbols-in-read-only-kexec_purgatory.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx>
Subject: kernel/kexec_file.c: search symbols in read-only kexec_purgatory
The stripped purgatory does not contain a symtab. So when looking for
symbols this is done in read-only kexec_purgatory. Highlight this by
marking the corresponding variables as 'const'.
Link: http://lkml.kernel.org/r/20180321112751.22196-5-prudo@xxxxxxxxxxxxxxxxxx
Signed-off-by: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx>
Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kexec_file.c | 38 ++++++++++++++++++++++----------------
1 file changed, 22 insertions(+), 16 deletions(-)
diff -puN kernel/kexec_file.c~kexec_file-search-symbols-in-read-only-kexec_purgatory kernel/kexec_file.c
--- a/kernel/kexec_file.c~kexec_file-search-symbols-in-read-only-kexec_purgatory
+++ a/kernel/kexec_file.c
@@ -1004,20 +1004,27 @@ out:
return ret;
}
-static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
- const char *name)
+/*
+ * kexec_purgatory_find_symbol - find a symbol in the purgatory
+ * @pi: Purgatory to search in.
+ * @name: Name of the symbol.
+ *
+ * Return: pointer to symbol in read-only symtab on success, NULL on error.
+ */
+static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
+ const char *name)
{
+ const Elf_Shdr *sechdrs;
const Elf_Ehdr *ehdr;
- Elf_Sym *syms;
- Elf_Shdr *sechdrs;
- int i, k;
+ const Elf_Sym *syms;
const char *strtab;
+ int i, k;
- if (!pi->sechdrs || !pi->ehdr)
+ if (!pi->ehdr)
return NULL;
- sechdrs = pi->sechdrs;
ehdr = pi->ehdr;
+ sechdrs = (void *)ehdr + ehdr->e_shoff;
for (i = 0; i < ehdr->e_shnum; i++) {
if (sechdrs[i].sh_type != SHT_SYMTAB)
@@ -1026,8 +1033,8 @@ static Elf_Sym *kexec_purgatory_find_sym
if (sechdrs[i].sh_link >= ehdr->e_shnum)
/* Invalid strtab section number */
continue;
- strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset;
- syms = (Elf_Sym *)sechdrs[i].sh_offset;
+ strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
+ syms = (void *)ehdr + sechdrs[i].sh_offset;
/* Go through symbols for a match */
for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
@@ -1055,7 +1062,7 @@ static Elf_Sym *kexec_purgatory_find_sym
void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
{
struct purgatory_info *pi = &image->purgatory_info;
- Elf_Sym *sym;
+ const Elf_Sym *sym;
Elf_Shdr *sechdr;
sym = kexec_purgatory_find_symbol(pi, name);
@@ -1078,9 +1085,9 @@ void *kexec_purgatory_get_symbol_addr(st
int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
void *buf, unsigned int size, bool get_value)
{
- Elf_Sym *sym;
- Elf_Shdr *sechdrs;
struct purgatory_info *pi = &image->purgatory_info;
+ const Elf_Sym *sym;
+ Elf_Shdr *sec;
char *sym_buf;
sym = kexec_purgatory_find_symbol(pi, name);
@@ -1093,16 +1100,15 @@ int kexec_purgatory_get_set_symbol(struc
return -EINVAL;
}
- sechdrs = pi->sechdrs;
+ sec = pi->sechdrs + sym->st_shndx;
- if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
+ if (sec->sh_type == SHT_NOBITS) {
pr_err("symbol %s is in a bss section. Cannot %s\n", name,
get_value ? "get" : "set");
return -EINVAL;
}
- sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset +
- sym->st_value;
+ sym_buf = (char *)sec->sh_offset + sym->st_value;
if (get_value)
memcpy((void *)buf, sym_buf, size);
_
Patches currently in -mm which might be from prudo@xxxxxxxxxxxxxxxxxx are
kexec_file-silence-compile-warnings.patch
kexec_file-remove-checks-in-kexec_purgatory_load.patch
kexec_file-make-purgatory_info-ehdr-const.patch
kexec_file-search-symbols-in-read-only-kexec_purgatory.patch
kexec_file-use-read-only-sections-in-arch_kexec_apply_relocations.patch
kexec_file-split-up-__kexec_load_puragory.patch
kexec_file-remove-unneeded-for-loop-in-kexec_purgatory_setup_sechdrs.patch
kexec_file-remove-unneeded-variables-in-kexec_purgatory_setup_sechdrs.patch
kexec_file-remove-mis-use-of-sh_offset-field-during-purgatory-load.patch
kexec_file-allow-archs-to-set-purgatory-load-address.patch
kexec_file-move-purgatories-sha256-to-common-code.patch
--
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