From bd40b17ca49d7d110adf456e647701ce74de2241 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 31 Jan 2020 05:07:55 -0500 Subject: XArray: Fix xa_find_next for large multi-index entries Coverity pointed out that xas_sibling() was shifting xa_offset without promoting it to an unsigned long first, so the shift could cause an overflow and we'd get the wrong answer. The fix is obvious, and the new test-case provokes UBSAN to report an error: runtime error: shift exponent 60 is too large for 32-bit type 'int' Fixes: 19c30f4dd092 ("XArray: Fix xa_find_after with multi-index entries") Reported-by: Bjorn Helgaas Reported-by: Kees Cook Signed-off-by: Matthew Wilcox (Oracle) Cc: stable@vger.kernel.org --- lib/test_xarray.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'lib/test_xarray.c') diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 55c14e8c8859..8c7d7a8468b8 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -12,6 +12,9 @@ static unsigned int tests_run; static unsigned int tests_passed; +static const unsigned int order_limit = + IS_ENABLED(CONFIG_XARRAY_MULTI) ? BITS_PER_LONG : 1; + #ifndef XA_DEBUG # ifdef __KERNEL__ void xa_dump(const struct xarray *xa) { } @@ -959,6 +962,20 @@ static noinline void check_multi_find_2(struct xarray *xa) } } +static noinline void check_multi_find_3(struct xarray *xa) +{ + unsigned int order; + + for (order = 5; order < order_limit; order++) { + unsigned long index = 1UL << (order - 5); + + XA_BUG_ON(xa, !xa_empty(xa)); + xa_store_order(xa, 0, order - 4, xa_mk_index(0), GFP_KERNEL); + XA_BUG_ON(xa, xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT)); + xa_erase_index(xa, 0); + } +} + static noinline void check_find_1(struct xarray *xa) { unsigned long i, j, k; @@ -1081,6 +1098,7 @@ static noinline void check_find(struct xarray *xa) for (i = 2; i < 10; i++) check_multi_find_1(xa, i); check_multi_find_2(xa); + check_multi_find_3(xa); } /* See find_swap_entry() in mm/shmem.c */ -- cgit v1.2.3-59-g8ed1b From c36d451ad386b34f452fc3c8621ff14b9eaa31a6 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 31 Jan 2020 06:17:09 -0500 Subject: XArray: Fix xas_pause for large multi-index entries Inspired by the recent Coverity report, I looked for other places where the offset wasn't being converted to an unsigned long before being shifted, and I found one in xas_pause() when the entry being paused is of order >32. Fixes: b803b42823d0 ("xarray: Add XArray iterators") Signed-off-by: Matthew Wilcox (Oracle) Cc: stable@vger.kernel.org --- lib/test_xarray.c | 37 +++++++++++++++++++++++++++++++++++++ lib/xarray.c | 2 +- 2 files changed, 38 insertions(+), 1 deletion(-) (limited to 'lib/test_xarray.c') diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 8c7d7a8468b8..d4f97925dbd8 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1156,6 +1156,42 @@ static noinline void check_find_entry(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_pause(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + void *entry; + unsigned int order; + unsigned long index = 1; + unsigned int count = 0; + + for (order = 0; order < order_limit; order++) { + XA_BUG_ON(xa, xa_store_order(xa, index, order, + xa_mk_index(index), GFP_KERNEL)); + index += 1UL << order; + } + + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + XA_BUG_ON(xa, entry != xa_mk_index(1UL << count)); + count++; + } + rcu_read_unlock(); + XA_BUG_ON(xa, count != order_limit); + + count = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + XA_BUG_ON(xa, entry != xa_mk_index(1UL << count)); + count++; + xas_pause(&xas); + } + rcu_read_unlock(); + XA_BUG_ON(xa, count != order_limit); + + xa_destroy(xa); +} + static noinline void check_move_tiny(struct xarray *xa) { XA_STATE(xas, xa, 0); @@ -1664,6 +1700,7 @@ static int xarray_checks(void) check_xa_alloc(); check_find(&array); check_find_entry(&array); + check_pause(&array); check_account(&array); check_destroy(&array); check_move(&array); diff --git a/lib/xarray.c b/lib/xarray.c index acd1fad2e862..05324cf571f4 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -970,7 +970,7 @@ void xas_pause(struct xa_state *xas) xas->xa_node = XAS_RESTART; if (node) { - unsigned int offset = xas->xa_offset; + unsigned long offset = xas->xa_offset; while (++offset < XA_CHUNK_SIZE) { if (!xa_is_sibling(xa_entry(xas->xa, node, offset))) break; -- cgit v1.2.3-59-g8ed1b