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Subject[PATCH v2 01/20] vmcore: refer to e_phoff member explicitly
Date
Code around /proc/vmcore currently assumes program header table is
next to ELF header. But future change can break the assumption on
kexec-tools and the 1st kernel. To avoid worst case, now refer to
e_phoff member that indicates position of program header table in
file-offset.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
---

fs/proc/vmcore.c | 40 ++++++++++++++++++++--------------------
1 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index b870f74..abf4f01 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -221,8 +221,8 @@ static u64 __init get_vmcore_size_elf64(char *elfptr)
Elf64_Phdr *phdr_ptr;

ehdr_ptr = (Elf64_Ehdr *)elfptr;
- phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
- size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
+ phdr_ptr = (Elf64_Phdr*)(elfptr + ehdr_ptr->e_phoff);
+ size = ehdr_ptr->e_phoff + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
for (i = 0; i < ehdr_ptr->e_phnum; i++) {
size += phdr_ptr->p_memsz;
phdr_ptr++;
@@ -238,8 +238,8 @@ static u64 __init get_vmcore_size_elf32(char *elfptr)
Elf32_Phdr *phdr_ptr;

ehdr_ptr = (Elf32_Ehdr *)elfptr;
- phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
- size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
+ phdr_ptr = (Elf32_Phdr*)(elfptr + ehdr_ptr->e_phoff);
+ size = ehdr_ptr->e_phoff + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
for (i = 0; i < ehdr_ptr->e_phnum; i++) {
size += phdr_ptr->p_memsz;
phdr_ptr++;
@@ -259,7 +259,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
u64 phdr_sz = 0, note_off;

ehdr_ptr = (Elf64_Ehdr *)elfptr;
- phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
+ phdr_ptr = (Elf64_Phdr*)(elfptr + ehdr_ptr->e_phoff);
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
int j;
void *notes_section;
@@ -305,7 +305,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
/* Prepare merged PT_NOTE program header. */
phdr.p_type = PT_NOTE;
phdr.p_flags = 0;
- note_off = sizeof(Elf64_Ehdr) +
+ note_off = ehdr_ptr->e_phoff +
(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
phdr.p_offset = note_off;
phdr.p_vaddr = phdr.p_paddr = 0;
@@ -313,14 +313,14 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
phdr.p_align = 0;

/* Add merged PT_NOTE program header*/
- tmp = elfptr + sizeof(Elf64_Ehdr);
+ tmp = elfptr + ehdr_ptr->e_phoff;
memcpy(tmp, &phdr, sizeof(phdr));
tmp += sizeof(phdr);

/* Remove unwanted PT_NOTE program headers. */
i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
*elfsz = *elfsz - i;
- memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
+ memmove(tmp, tmp+i, ((*elfsz)-ehdr_ptr->e_phoff-sizeof(Elf64_Phdr)));

/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
@@ -340,7 +340,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
u64 phdr_sz = 0, note_off;

ehdr_ptr = (Elf32_Ehdr *)elfptr;
- phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
+ phdr_ptr = (Elf32_Phdr*)(elfptr + ehdr_ptr->e_phoff);
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
int j;
void *notes_section;
@@ -386,7 +386,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
/* Prepare merged PT_NOTE program header. */
phdr.p_type = PT_NOTE;
phdr.p_flags = 0;
- note_off = sizeof(Elf32_Ehdr) +
+ note_off = ehdr_ptr->e_phoff +
(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
phdr.p_offset = note_off;
phdr.p_vaddr = phdr.p_paddr = 0;
@@ -394,14 +394,14 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
phdr.p_align = 0;

/* Add merged PT_NOTE program header*/
- tmp = elfptr + sizeof(Elf32_Ehdr);
+ tmp = elfptr + ehdr_ptr->e_phoff;
memcpy(tmp, &phdr, sizeof(phdr));
tmp += sizeof(phdr);

/* Remove unwanted PT_NOTE program headers. */
i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
*elfsz = *elfsz - i;
- memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
+ memmove(tmp, tmp+i, ((*elfsz)-ehdr_ptr->e_phoff-sizeof(Elf32_Phdr)));

/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
@@ -422,10 +422,10 @@ static int __init process_ptload_program_headers_elf64(char *elfptr,
struct vmcore *new;

ehdr_ptr = (Elf64_Ehdr *)elfptr;
- phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
+ phdr_ptr = (Elf64_Phdr*)(elfptr + ehdr_ptr->e_phoff); /* PT_NOTE hdr */

/* First program header is PT_NOTE header. */
- vmcore_off = sizeof(Elf64_Ehdr) +
+ vmcore_off = ehdr_ptr->e_phoff +
(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
phdr_ptr->p_memsz; /* Note sections */

@@ -459,10 +459,10 @@ static int __init process_ptload_program_headers_elf32(char *elfptr,
struct vmcore *new;

ehdr_ptr = (Elf32_Ehdr *)elfptr;
- phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
+ phdr_ptr = (Elf32_Phdr*)(elfptr + ehdr_ptr->e_phoff); /* PT_NOTE hdr */

/* First program header is PT_NOTE header. */
- vmcore_off = sizeof(Elf32_Ehdr) +
+ vmcore_off = ehdr_ptr->e_phoff +
(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
phdr_ptr->p_memsz; /* Note sections */

@@ -496,7 +496,7 @@ static void __init set_vmcore_list_offsets_elf64(char *elfptr,
ehdr_ptr = (Elf64_Ehdr *)elfptr;

/* Skip Elf header and program headers. */
- vmcore_off = sizeof(Elf64_Ehdr) +
+ vmcore_off = ehdr_ptr->e_phoff +
(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);

list_for_each_entry(m, vc_list, list) {
@@ -516,7 +516,7 @@ static void __init set_vmcore_list_offsets_elf32(char *elfptr,
ehdr_ptr = (Elf32_Ehdr *)elfptr;

/* Skip Elf header and program headers. */
- vmcore_off = sizeof(Elf32_Ehdr) +
+ vmcore_off = ehdr_ptr->e_phoff +
(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);

list_for_each_entry(m, vc_list, list) {
@@ -553,7 +553,7 @@ static int __init parse_crash_elf64_headers(void)
}

/* Read in all elf headers. */
- elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
+ elfcorebuf_sz = ehdr.e_phoff + ehdr.e_phnum * sizeof(Elf64_Phdr);
elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
if (!elfcorebuf)
return -ENOMEM;
@@ -608,7 +608,7 @@ static int __init parse_crash_elf32_headers(void)
}

/* Read in all elf headers. */
- elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
+ elfcorebuf_sz = ehdr.e_phoff + ehdr.e_phnum * sizeof(Elf32_Phdr);
elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
if (!elfcorebuf)
return -ENOMEM;


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