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authorAndrey Ryabinin <ryabinin.a.a@gmail.com>2021-02-25 17:22:42 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:05 -0800
commit6aaa31aeb9cf260e1b7155cc11ec864f052db5ec (patch)
tree4546f94fd7723de6c3c700b0eac658e910c63e30 /lib/ubsan.c
parentd54ce6158e354f5358a547b96299ecd7f3725393 (diff)
ubsan: remove overflow checks
Since GCC 8.0 -fsanitize=signed-integer-overflow doesn't work with -fwrapv. -fwrapv makes signed overflows defines and GCC essentially disables ubsan checks. On GCC < 8.0 -fwrapv doesn't have influence on -fsanitize=signed-integer-overflow setting, so it kinda works but generates false-positves and violates uaccess rules: lib/iov_iter.o: warning: objtool: iovec_from_user()+0x22d: call to __ubsan_handle_add_overflow() with UACCESS enabled Disable signed overflow checks to avoid these problems. Remove unsigned overflow checks as well. Unsigned overflow appeared as side effect of commit cdf8a76fda4a ("ubsan: move cc-option tests into Kconfig"), but it never worked (kernel doesn't boot). And unsigned overflows are allowed by C standard, so it just pointless. Link: https://lkml.kernel.org/r/20210209232348.20510-1-ryabinin.a.a@gmail.com Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/ubsan.c')
-rw-r--r--lib/ubsan.c68
1 files changed, 0 insertions, 68 deletions
diff --git a/lib/ubsan.c b/lib/ubsan.c
index bec38c64d6a6..26229973049d 100644
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -163,74 +163,6 @@ static void ubsan_epilogue(void)
}
}
-static void handle_overflow(struct overflow_data *data, void *lhs,
- void *rhs, char op)
-{
-
- struct type_descriptor *type = data->type;
- char lhs_val_str[VALUE_LENGTH];
- char rhs_val_str[VALUE_LENGTH];
-
- if (suppress_report(&data->location))
- return;
-
- ubsan_prologue(&data->location, type_is_signed(type) ?
- "signed-integer-overflow" :
- "unsigned-integer-overflow");
-
- val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
- val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
- pr_err("%s %c %s cannot be represented in type %s\n",
- lhs_val_str,
- op,
- rhs_val_str,
- type->type_name);
-
- ubsan_epilogue();
-}
-
-void __ubsan_handle_add_overflow(void *data,
- void *lhs, void *rhs)
-{
-
- handle_overflow(data, lhs, rhs, '+');
-}
-EXPORT_SYMBOL(__ubsan_handle_add_overflow);
-
-void __ubsan_handle_sub_overflow(void *data,
- void *lhs, void *rhs)
-{
- handle_overflow(data, lhs, rhs, '-');
-}
-EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
-
-void __ubsan_handle_mul_overflow(void *data,
- void *lhs, void *rhs)
-{
- handle_overflow(data, lhs, rhs, '*');
-}
-EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
-
-void __ubsan_handle_negate_overflow(void *_data, void *old_val)
-{
- struct overflow_data *data = _data;
- char old_val_str[VALUE_LENGTH];
-
- if (suppress_report(&data->location))
- return;
-
- ubsan_prologue(&data->location, "negation-overflow");
-
- val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);
-
- pr_err("negation of %s cannot be represented in type %s:\n",
- old_val_str, data->type->type_name);
-
- ubsan_epilogue();
-}
-EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
-
-
void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
{
struct overflow_data *data = _data;