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authorArnd Bergmann <arnd@arndb.de>2022-02-10 16:24:30 +0100
committerArnd Bergmann <arnd@arndb.de>2022-02-14 22:30:53 +0100
commit222ca305c9fd39e5ed8104da25c09b2b79a516a8 (patch)
tree226513c6b142c9fab9582d776f77d00e2cbee47c /arch/microblaze
parentdfd42facf1e4ada021b939b4e19c935dcdd55566 (diff)
uaccess: fix integer overflow on access_ok()
Three architectures check the end of a user access against the address limit without taking a possible overflow into account. Passing a negative length or another overflow in here returns success when it should not. Use the most common correct implementation here, which optimizes for a constant 'size' argument, and turns the common case into a single comparison. Cc: stable@vger.kernel.org Fixes: da551281947c ("csky: User access") Fixes: f663b60f5215 ("microblaze: Fix uaccess_ok macro") Fixes: 7567746e1c0d ("Hexagon: Add user access functions") Reported-by: David Laight <David.Laight@aculab.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/microblaze')
-rw-r--r--arch/microblaze/include/asm/uaccess.h19
1 files changed, 4 insertions, 15 deletions
diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index d2a8ef9f8978..5b6e0e7788f4 100644
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -39,24 +39,13 @@
# define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-static inline int access_ok(const void __user *addr, unsigned long size)
+static inline int __access_ok(unsigned long addr, unsigned long size)
{
- if (!size)
- goto ok;
+ unsigned long limit = user_addr_max();
- if ((get_fs().seg < ((unsigned long)addr)) ||
- (get_fs().seg < ((unsigned long)addr + size - 1))) {
- pr_devel("ACCESS fail at 0x%08x (size 0x%x), seg 0x%08x\n",
- (__force u32)addr, (u32)size,
- (u32)get_fs().seg);
- return 0;
- }
-ok:
- pr_devel("ACCESS OK at 0x%08x (size 0x%x), seg 0x%08x\n",
- (__force u32)addr, (u32)size,
- (u32)get_fs().seg);
- return 1;
+ return (size <= limit) && (addr <= (limit - size));
}
+#define access_ok(addr, size) __access_ok((unsigned long)addr, size)
# define __FIXUP_SECTION ".section .fixup,\"ax\"\n"
# define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n"