binfmt_flat: add endianess annotations

Most binfmt_flat on-disk fields are big endian.  Use the proper __be32
type where applicable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

Author: Christoph Hellwig

fs/binfmt_flat.c

@@ -421,7 +421,8 @@ static int load_flat_file(struct linux_binprm *bprm,
 	unsigned long textpos, datapos, realdatastart;
 	u32 text_len, data_len, bss_len, stack_len, full_data, flags;
 	unsigned long len, memp, memp_size, extra, rlim;
-	u32 __user *reloc, *rp;
+	__be32 __user *reloc;
+	u32 __user *rp;
 	struct inode *inode;
 	int i, rev, relocs;
 	loff_t fpos;
@@ -594,7 +595,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 			goto err;
 		}
 
-		reloc = (u32 __user *)
+		reloc = (__be32 __user *)
 			(datapos + (ntohl(hdr->reloc_start) - text_len));
 		memp = realdatastart;
 		memp_size = len;
@@ -619,7 +620,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 				MAX_SHARED_LIBS * sizeof(u32),
 				FLAT_DATA_ALIGN);
 
-		reloc = (u32 __user *)
+		reloc = (__be32 __user *)
 			(datapos + (ntohl(hdr->reloc_start) - text_len));
 		memp = textpos;
 		memp_size = len;
@@ -785,15 +786,16 @@ static int load_flat_file(struct linux_binprm *bprm,
 		u32 __maybe_unused persistent = 0;
 		for (i = 0; i < relocs; i++) {
 			u32 addr, relval;
+			__be32 tmp;
 
 			/*
 			 * Get the address of the pointer to be
 			 * relocated (of course, the address has to be
 			 * relocated first).
 			 */
-			if (get_user(relval, reloc + i))
+			if (get_user(tmp, reloc + i))
 				return -EFAULT;
-			relval = ntohl(relval);
+			relval = ntohl(tmp);
 			addr = flat_get_relocate_addr(relval);
 			rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
 			if (rp == (u32 __user *)RELOC_FAILED) {
@@ -812,8 +814,13 @@ static int load_flat_file(struct linux_binprm *bprm,
 				 * Do the relocation.  PIC relocs in the data section are
 				 * already in target order
 				 */
-				if ((flags & FLAT_FLAG_GOTPIC) == 0)
-					addr = ntohl(addr);
+				if ((flags & FLAT_FLAG_GOTPIC) == 0) {
+					/*
+					 * Meh, the same value can have a different
+					 * byte order based on a flag..
+					 */
+					addr = ntohl((__force __be32)addr);
+				}
 				addr = calc_reloc(addr, libinfo, id, 0);
 				if (addr == RELOC_FAILED) {
 					ret = -ENOEXEC;
@@ -828,11 +835,10 @@ static int load_flat_file(struct linux_binprm *bprm,
 		}
 	} else {
 		for (i = 0; i < relocs; i++) {
-			u32 relval;
+			__be32 relval;
 			if (get_user(relval, reloc + i))
 				return -EFAULT;
-			relval = ntohl(relval);
-			old_reloc(relval);
+			old_reloc(ntohl(relval));
 		}
 	}