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authorDavid Howells <dhowells@redhat.com>2009-09-23 18:57:06 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-24 10:21:02 -0400
commit8e8b63a68c7ec95ef23770813120f4f98c76e08b (patch)
tree82339b06388b2002557ec5fab7dcfa72c918b3c6 /fs/binfmt_elf_fdpic.c
parent0cf062d0ffa33d491e2695b0d298ccf9cbb58d3d (diff)
fdpic: ignore the loader's PT_GNU_STACK when calculating the stack size
Ignore the loader's PT_GNU_STACK when calculating the stack size, and only consider the executable's PT_GNU_STACK, assuming the executable has one. Currently the behaviour is to take the largest stack size and use that, but that means you can't reduce the stack size in the executable. The loader's stack size should probably only be used when executing the loader directly. WARNING: This patch is slightly dangerous - it may render a system inoperable if the loader's stack size is larger than that of important executables, and the system relies unknowingly on this increasing the size of the stack. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/binfmt_elf_fdpic.c')
-rw-r--r--fs/binfmt_elf_fdpic.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 76285471073e..38502c67987c 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -283,20 +283,23 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
283 } 283 }
284 284
285 stack_size = exec_params.stack_size; 285 stack_size = exec_params.stack_size;
286 if (stack_size < interp_params.stack_size)
287 stack_size = interp_params.stack_size;
288
289 if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK) 286 if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
290 executable_stack = EXSTACK_ENABLE_X; 287 executable_stack = EXSTACK_ENABLE_X;
291 else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK) 288 else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
292 executable_stack = EXSTACK_DISABLE_X; 289 executable_stack = EXSTACK_DISABLE_X;
293 else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
294 executable_stack = EXSTACK_ENABLE_X;
295 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
296 executable_stack = EXSTACK_DISABLE_X;
297 else 290 else
298 executable_stack = EXSTACK_DEFAULT; 291 executable_stack = EXSTACK_DEFAULT;
299 292
293 if (stack_size == 0) {
294 stack_size = interp_params.stack_size;
295 if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
296 executable_stack = EXSTACK_ENABLE_X;
297 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
298 executable_stack = EXSTACK_DISABLE_X;
299 else
300 executable_stack = EXSTACK_DEFAULT;
301 }
302
300 retval = -ENOEXEC; 303 retval = -ENOEXEC;
301 if (stack_size == 0) 304 if (stack_size == 0)
302 goto error; 305 goto error;