[PATCH v2 01/20] vmcore: refer to e_phoff member explicitly

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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 at 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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