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authorPhilipp Rudo <prudo@linux.vnet.ibm.com>2018-04-13 15:36:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-13 17:10:28 -0700
commit961d921a1b967f76e13f9e11f2b0c2bcb5741f10 (patch)
tree4934f6507ab82fa24bed42bd7ae71640bd5aeb3f
parent65c225d3280542f3ea145e052215ce0538f6bb69 (diff)
downloadlinux-stericsson-961d921a1b967f76e13f9e11f2b0c2bcb5741f10.tar.gz
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@linux.vnet.ibm.com Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/kexec_file.c38
1 files changed, 22 insertions, 16 deletions
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 12cf9c9ff0bc..9bd1ec1dd875 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -962,20 +962,27 @@ 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)
@@ -984,8 +991,8 @@ static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
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++) {
@@ -1013,7 +1020,7 @@ static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
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);
@@ -1036,9 +1043,9 @@ void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
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);
@@ -1051,16 +1058,15 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
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);