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Subject[PATCH] Fix some ELF-FDPIC binfmt problems
Date

The attached patch fixes the following problems in the ELF-FDPIC binfmt
driver:

(1) elf_fdpic_map_file() should be passed an mm_struct pointer, not NULL.

(2) do_mmap() should be called with the mmap_sem held.

(3) mm_struct::end_brk doesn't exist in 2.6 (debugging only).

(4) Avoid debugging warnings by casting certain values to unsigned long
before printing them.

Signed-Off-By: David Howells <dhowells@redhat.com>
---
warthog>diffstat elf-fdpic-2610rc2mm3-3.diff
binfmt_elf_fdpic.c | 20 ++++++++++++++------
1 files changed, 14 insertions(+), 6 deletions(-)
diff -uNrp linux-2.6.10-rc2-mm3-mmcleanup/fs/binfmt_elf_fdpic.c linux-2.6.10-rc2-mm3-shmem/fs/binfmt_elf_fdpic.c
--- linux-2.6.10-rc2-mm3-mmcleanup/fs/binfmt_elf_fdpic.c 2004-11-22 10:54:09.000000000 +0000
+++ linux-2.6.10-rc2-mm3-shmem/fs/binfmt_elf_fdpic.c 2004-12-01 16:31:43.000000000 +0000
@@ -315,7 +315,8 @@ static int load_elf_fdpic_binary(struct
goto error_kill;

if (interpreter_name) {
- retval = elf_fdpic_map_file(&interp_params, interpreter, NULL, "interpreter");
+ retval = elf_fdpic_map_file(&interp_params, interpreter,
+ current->mm, "interpreter");
if (retval < 0) {
printk(KERN_ERR "Unable to load interpreter\n");
goto error_kill;
@@ -341,6 +342,7 @@ static int load_elf_fdpic_binary(struct
if (stack_size < PAGE_SIZE * 2)
stack_size = PAGE_SIZE * 2;

+ down_write(&current->mm->mmap_sem);
current->mm->start_brk = do_mmap(NULL,
0,
stack_size,
@@ -349,12 +351,12 @@ static int load_elf_fdpic_binary(struct
0);

if (IS_ERR((void *) current->mm->start_brk)) {
+ up_write(&current->mm->mmap_sem);
retval = current->mm->start_brk;
current->mm->start_brk = 0;
goto error_kill;
}

- down_write(&current->mm->mmap_sem);
if (do_mremap(current->mm->start_brk,
stack_size,
ksize((char *) current->mm->start_brk),
@@ -381,9 +383,6 @@ static int load_elf_fdpic_binary(struct
kdebug("- end_data %lx", (long) current->mm->end_data);
kdebug("- start_brk %lx", (long) current->mm->start_brk);
kdebug("- brk %lx", (long) current->mm->brk);
-#ifndef CONFIG_MMU
- kdebug("- end_brk %lx", (long) current->mm->end_brk);
-#endif
kdebug("- start_stack %lx", (long) current->mm->start_stack);

#ifdef ELF_FDPIC_PLAT_INIT
@@ -870,8 +869,10 @@ static int elf_fdpic_map_file_constdisp_
if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
mflags |= MAP_EXECUTABLE;

+ down_write(&mm->mmap_sem);
maddr = do_mmap(NULL, load_addr, top - base,
PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
+ up_write(&mm->mmap_sem);
if (IS_ERR((void *) maddr))
return (int) maddr;

@@ -957,7 +958,10 @@ static int elf_fdpic_map_file_by_direct_
continue;

kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
- phdr->p_vaddr, phdr->p_offset, phdr->p_filesz, phdr->p_memsz);
+ (unsigned long) phdr->p_vaddr,
+ (unsigned long) phdr->p_offset,
+ (unsigned long) phdr->p_filesz,
+ (unsigned long) phdr->p_memsz);

/* determine the mapping parameters */
if (phdr->p_flags & PF_R) prot |= PROT_READ;
@@ -1008,8 +1012,10 @@ static int elf_fdpic_map_file_by_direct_

/* create the mapping */
disp = phdr->p_vaddr & ~PAGE_MASK;
+ down_write(&mm->mmap_sem);
maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
phdr->p_offset - disp);
+ up_write(&mm->mmap_sem);

kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
@@ -1051,7 +1057,9 @@ static int elf_fdpic_map_file_by_direct_
unsigned long xmaddr;

flags |= MAP_FIXED | MAP_ANONYMOUS;
+ down_write(&mm->mmap_sem);
xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
+ up_write(&mm->mmap_sem);

kdebug("mmap[%d] <anon>"
" ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
-
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