From d41519a69b35b10af7fda867fb9100df24fdf403 Mon Sep 17 00:00:00 2001 From: David Miller Date: Fri, 2 Jun 2017 11:28:54 -0400 Subject: crypto: Work around deallocated stack frame reference gcc bug on sparc. On sparc, if we have an alloca() like situation, as is the case with SHASH_DESC_ON_STACK(), we can end up referencing deallocated stack memory. The result can be that the value is clobbered if a trap or interrupt arrives at just the right instruction. It only occurs if the function ends returning a value from that alloca() area and that value can be placed into the return value register using a single instruction. For example, in lib/libcrc32c.c:crc32c() we end up with a return sequence like: return %i7+8 lduw [%o5+16], %o0 ! MEM[(u32 *)__shash_desc.1_10 + 16B], %o5 holds the base of the on-stack area allocated for the shash descriptor. But the return released the stack frame and the register window. So if an intererupt arrives between 'return' and 'lduw', then the value read at %o5+16 can be corrupted. Add a data compiler barrier to work around this problem. This is exactly what the gcc fix will end up doing as well, and it absolutely should not change the code generated for other cpus (unless gcc on them has the same bug :-) With crucial insight from Eric Sandeen. Cc: Reported-by: Anatoly Pugachev Signed-off-by: David S. Miller Signed-off-by: Herbert Xu --- lib/libcrc32c.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c index 74a54b7f2562..9f79547d1b97 100644 --- a/lib/libcrc32c.c +++ b/lib/libcrc32c.c @@ -43,7 +43,7 @@ static struct crypto_shash *tfm; u32 crc32c(u32 crc, const void *address, unsigned int length) { SHASH_DESC_ON_STACK(shash, tfm); - u32 *ctx = (u32 *)shash_desc_ctx(shash); + u32 ret, *ctx = (u32 *)shash_desc_ctx(shash); int err; shash->tfm = tfm; @@ -53,7 +53,9 @@ u32 crc32c(u32 crc, const void *address, unsigned int length) err = crypto_shash_update(shash, address, length); BUG_ON(err); - return *ctx; + ret = *ctx; + barrier_data(ctx); + return ret; } EXPORT_SYMBOL(crc32c); -- cgit v1.3-14-g43fede From a91e0f680bcd9e10c253ae8b62462a38bd48f09f Mon Sep 17 00:00:00 2001 From: Ilya Matveychikov Date: Fri, 23 Jun 2017 15:08:49 -0700 Subject: lib/cmdline.c: fix get_options() overflow while parsing ranges When using get_options() it's possible to specify a range of numbers, like 1-100500. The problem is that it doesn't track array size while calling internally to get_range() which iterates over the range and fills the memory with numbers. Link: http://lkml.kernel.org/r/2613C75C-B04D-4BFF-82A6-12F97BA0F620@gmail.com Signed-off-by: Ilya V. Matveychikov Cc: Jonathan Corbet Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/cmdline.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/cmdline.c b/lib/cmdline.c index 3c6432df7e63..4c0888c4a68d 100644 --- a/lib/cmdline.c +++ b/lib/cmdline.c @@ -23,14 +23,14 @@ * the values[M, M+1, ..., N] into the ints array in get_options. */ -static int get_range(char **str, int *pint) +static int get_range(char **str, int *pint, int n) { int x, inc_counter, upper_range; (*str)++; upper_range = simple_strtol((*str), NULL, 0); inc_counter = upper_range - *pint; - for (x = *pint; x < upper_range; x++) + for (x = *pint; n && x < upper_range; x++, n--) *pint++ = x; return inc_counter; } @@ -97,7 +97,7 @@ char *get_options(const char *str, int nints, int *ints) break; if (res == 3) { int range_nums; - range_nums = get_range((char **)&str, ints + i); + range_nums = get_range((char **)&str, ints + i, nints - i); if (range_nums < 0) break; /* -- cgit v1.3-14-g43fede