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Subject[PATCH 08/10] binfmt_flat: update libraries' data segment pointer with userspace accessors
Date
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 <nico@linaro.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 e981e66bb5..3221ed9d7c 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -902,12 +902,19 @@ 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
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