[PATCH v3 12/12] binfmt_flat: allow compressed flat binary format to work on MMU systems

[Nicolas Pitre]

Let's take the simple and obvious approach by decompressing the binary
into a kernel buffer and then copying it to user space.  Those who are
looking for top performance on an MMU system are unlikely to choose this
executable format anyway.

Signed-off-by: Nicolas Pitre 
Reviewed-by: Greg Ungerer 
---
 fs/binfmt_flat.c | 44 ++--
 1 file changed, 42 insertions(+), 2 deletions(-)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index d04188267a..8dac70921b 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -37,6 +37,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -632,6 +633,7 @@ static int load_flat_file(struct linux_binprm * bprm,
 * load it all in and treat it like a RAM load from now on
 */
if (flags & FLAT_FLAG_GZIP) {
+#ifndef CONFIG_MMU
result = decompress_exec(bprm, sizeof (struct flat_hdr),
 (((char *) textpos) + sizeof (struct 
flat_hdr)),
 (text_len + full_data
@@ -639,14 +641,52 @@ static int load_flat_file(struct linux_binprm * bprm,
 0);
memmove((void *) datapos, (void *) realdatastart,
full_data);
+#else
+   /*
+* This is used on MMU systems mainly for testing.
+* Let's use a kernel buffer to simplify things.
+*/
+   long unz_text_len = text_len - sizeof(struct flat_hdr);
+   long unz_len = unz_text_len + full_data;
+   char *unz_data = vmalloc(unz_len);
+   if (!unz_data) {
+   result = -ENOMEM;
+   } else {
+   result = decompress_exec(bprm, sizeof(struct 
flat_hdr),
+unz_data, unz_len, 0);
+   if (result == 0 &&
+   (copy_to_user((void __user *)textpos + 
sizeof(struct flat_hdr),
+ unz_data, unz_text_len) ||
+copy_to_user((void __user *)datapos,
+ unz_data + unz_text_len, 
full_data)))
+   result = -EFAULT;
+   vfree(unz_data);
+   }
+#endif
} else if (flags & FLAT_FLAG_GZDATA) {
result = read_code(bprm->file, textpos, 0, text_len);
-   if (!IS_ERR_VALUE(result))
+   if (!IS_ERR_VALUE(result)) {
+#ifndef CONFIG_MMU
result = decompress_exec(bprm, text_len, (char 
*) datapos,
 full_data, 0);
+#else
+   char *unz_data = vmalloc(full_data);
+   if (!unz_data) {
+   result = -ENOMEM;
+   } else {
+   result = decompress_exec(bprm, text_len,
+  unz_data, full_data, 0);
+   if (result == 0 &&
+   copy_to_user((void __user *)datapos,
+unz_data, full_data))
+   result = -EFAULT;
+   vfree(unz_data);
+   }
+#endif
+   }
}
else
-#endif
+#endif /* CONFIG_BINFMT_ZFLAT */
{
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result))
-- 
2.7.4

[PATCH v3 12/12] binfmt_flat: allow compressed flat binary format to work on MMU systems

[Nicolas Pitre]

Let's take the simple and obvious approach by decompressing the binary
into a kernel buffer and then copying it to user space.  Those who are
looking for top performance on an MMU system are unlikely to choose this
executable format anyway.

Signed-off-by: Nicolas Pitre 
Reviewed-by: Greg Ungerer 
---
 fs/binfmt_flat.c | 44 ++--
 1 file changed, 42 insertions(+), 2 deletions(-)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index d04188267a..8dac70921b 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -37,6 +37,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -632,6 +633,7 @@ static int load_flat_file(struct linux_binprm * bprm,
 * load it all in and treat it like a RAM load from now on
 */
if (flags & FLAT_FLAG_GZIP) {
+#ifndef CONFIG_MMU
result = decompress_exec(bprm, sizeof (struct flat_hdr),
 (((char *) textpos) + sizeof (struct 
flat_hdr)),
 (text_len + full_data
@@ -639,14 +641,52 @@ static int load_flat_file(struct linux_binprm * bprm,
 0);
memmove((void *) datapos, (void *) realdatastart,
full_data);
+#else
+   /*
+* This is used on MMU systems mainly for testing.
+* Let's use a kernel buffer to simplify things.
+*/
+   long unz_text_len = text_len - sizeof(struct flat_hdr);
+   long unz_len = unz_text_len + full_data;
+   char *unz_data = vmalloc(unz_len);
+   if (!unz_data) {
+   result = -ENOMEM;
+   } else {
+   result = decompress_exec(bprm, sizeof(struct 
flat_hdr),
+unz_data, unz_len, 0);
+   if (result == 0 &&
+   (copy_to_user((void __user *)textpos + 
sizeof(struct flat_hdr),
+ unz_data, unz_text_len) ||
+copy_to_user((void __user *)datapos,
+ unz_data + unz_text_len, 
full_data)))
+   result = -EFAULT;
+   vfree(unz_data);
+   }
+#endif
} else if (flags & FLAT_FLAG_GZDATA) {
result = read_code(bprm->file, textpos, 0, text_len);
-   if (!IS_ERR_VALUE(result))
+   if (!IS_ERR_VALUE(result)) {
+#ifndef CONFIG_MMU
result = decompress_exec(bprm, text_len, (char 
*) datapos,
 full_data, 0);
+#else
+   char *unz_data = vmalloc(full_data);
+   if (!unz_data) {
+   result = -ENOMEM;
+   } else {
+   result = decompress_exec(bprm, text_len,
+  unz_data, full_data, 0);
+   if (result == 0 &&
+   copy_to_user((void __user *)datapos,
+unz_data, full_data))
+   result = -EFAULT;
+   vfree(unz_data);
+   }
+#endif
+   }
}
else
-#endif
+#endif /* CONFIG_BINFMT_ZFLAT */
{
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result))
-- 
2.7.4