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Groups > linux.kernel > #1441754

[PATCH 06/10] binfmt_flat: use proper user space accessors with old relocs code

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Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
 fs/binfmt_flat.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index fc0ee3ed5d..c85f8f1239 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -394,38 +394,41 @@ static void old_reloc(unsigned long rl)
 	static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 #endif
 	flat_v2_reloc_t	r;
-	unsigned long *ptr;
+	unsigned long __user *ptr;
+	unsigned long val;
 	
 	r.value = rl;
 #if defined(CONFIG_COLDFIRE)
-	ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
+	ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
 #else
-	ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
+	ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
 #endif
+	__get_user(val, ptr);
 
 #ifdef DEBUG
 	printk("Relocation of variable at DATASEG+%x "
 		"(address %p, currently %lx) into segment %s\n",
-		r.reloc.offset, ptr, *ptr, segment[r.reloc.type]);
+		r.reloc.offset, ptr, val, segment[r.reloc.type]);
 #endif
 	
 	switch (r.reloc.type) {
 	case OLD_FLAT_RELOC_TYPE_TEXT:
-		*ptr += current->mm->start_code;
+		val += current->mm->start_code;
 		break;
 	case OLD_FLAT_RELOC_TYPE_DATA:
-		*ptr += current->mm->start_data;
+		val += current->mm->start_data;
 		break;
 	case OLD_FLAT_RELOC_TYPE_BSS:
-		*ptr += current->mm->end_data;
+		val += current->mm->end_data;
 		break;
 	default:
 		printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
 		break;
 	}
+	__put_user(val, ptr);
 
 #ifdef DEBUG
-	printk("Relocation became %lx\n", *ptr);
+	printk("Relocation became %lx\n", val);
 #endif
 }		
 
@@ -788,8 +791,13 @@ static int load_flat_file(struct linux_binprm * bprm,
 			}
 		}
 	} else {
-		for (i=0; i < relocs; i++)
-			old_reloc(ntohl(reloc[i]));
+		for (i=0; i < relocs; i++) {
+			unsigned long relval;
+			if (get_user(relval, reloc + i))
+				return -EFAULT;
+			relval = ntohl(relval);
+			old_reloc(relval);
+		}
 	}
 	
 	flush_icache_range(start_code, end_code);
-- 
2.7.4

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[PATCH 00/10] allow BFLT executables on systems with a MMU Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  07/10] binfmt_flat: use clear_user() rather than memset() to clear .bss Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  09/10] binfmt_flat: add MMU-specific support Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  03/10] binfmt_flat: use generic transfer_args_to_stack() Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  05/10] binfmt_flat: use proper user space accessors with relocs processing code Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  01/10] binfmt_flat: assorted cleanups Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  10/10] binfmt_flat: allow compressed flat binary format to work on MMU systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  08/10] binfmt_flat: update libraries' data segment pointer with userspace accessors Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  06/10] binfmt_flat: use proper user space accessors with old relocs code Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  02/10] elf_fdpic_transfer_args_to_stack(): make it generic Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
  [PATCH  04/10] binfmt_flat: clean up create_flat_tables() and stack accesses Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200

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