[PATCH v5 10/15] binfmt_flat: update libraries' data segment pointer with userspace accessors
From: Nicolas Pitre <hidden>
Date: 2016-07-24 15:30:41
Also in:
linux-fsdevel, lkml
Subsystem:
exec & binfmt api, elf, filesystems (vfs and infrastructure), the rest · Maintainers:
Kees Cook, Alexander Viro, Christian Brauner, Linus Torvalds
This is needed on systems with a MMU. This also gets rid of the strangest C code I've seen lateli i.e. an integer indexed with a pointer value within square brackets. That really looked backwards. Signed-off-by: Nicolas Pitre <redacted> Reviewed-by: Greg Ungerer <gerg@linux-m68k.org> --- fs/binfmt_flat.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 92c1530a2c..aa7971ce6a 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c@@ -894,12 +894,19 @@ static int load_flat_binary(struct linux_binprm *bprm) return res; /* Update data segment pointers for all libraries */ - for (i = 0; i < MAX_SHARED_LIBS; i++) - if (libinfo.lib_list[i].loaded) - for (j = 0; j < MAX_SHARED_LIBS; j++) - (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] = - (libinfo.lib_list[j].loaded) ? - libinfo.lib_list[j].start_data : UNLOADED_LIB; + for (i = 0; i < MAX_SHARED_LIBS; i++) { + if (!libinfo.lib_list[i].loaded) + continue; + for (j = 0; j < MAX_SHARED_LIBS; j++) { + unsigned long val = libinfo.lib_list[j].loaded ? + libinfo.lib_list[j].start_data : UNLOADED_LIB; + unsigned long __user *p = (unsigned long __user *) + libinfo.lib_list[i].start_data; + p -= j + 1; + if (put_user(val, p)) + return -EFAULT; + } + } install_exec_creds(bprm);
--
2.7.4