[PATCH v3] bootconfig: use memblock_free_late to free xbc memory to buddy
From: Qiang Zhang On the time to free xbc memory in xbc_exit(), memblock may has handed over memory to buddy allocator. So it doesn't make sense to free memory back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86. Following KASAN logs shows this case. This patch fixes the xbc memory free problem by calling memblock_free() in early xbc init error rewind path and calling memblock_free_late() in xbc exit path to free memory to buddy allocator. [9.410890] == [9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260 [9.426850] Read of size 8 at addr 88845dd3 by task swapper/0/1 [9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5 [9.446403] Hardware name: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D- Dec 28 2023 [9.460789] Call Trace: [9.463518] [9.465859] dump_stack_lvl+0x53/0x70 [9.469949] print_report+0xce/0x610 [9.473944] ? __virt_addr_valid+0xf5/0x1b0 [9.478619] ? memblock_isolate_range+0x12d/0x260 [9.483877] kasan_report+0xc6/0x100 [9.487870] ? memblock_isolate_range+0x12d/0x260 [9.493125] memblock_isolate_range+0x12d/0x260 [9.498187] memblock_phys_free+0xb4/0x160 [9.502762] ? __pfx_memblock_phys_free+0x10/0x10 [9.508021] ? mutex_unlock+0x7e/0xd0 [9.512111] ? __pfx_mutex_unlock+0x10/0x10 [9.516786] ? kernel_init_freeable+0x2d4/0x430 [9.521850] ? __pfx_kernel_init+0x10/0x10 [9.526426] xbc_exit+0x17/0x70 [9.529935] kernel_init+0x38/0x1e0 [9.533829] ? _raw_spin_unlock_irq+0xd/0x30 [9.538601] ret_from_fork+0x2c/0x50 [9.542596] ? __pfx_kernel_init+0x10/0x10 [9.547170] ret_from_fork_asm+0x1a/0x30 [9.551552] [9.555649] The buggy address belongs to the physical page: [9.561875] page: refcount:0 mapcount:0 mapping: index:0x1 pfn:0x45dd30 [9.570821] flags: 0x200(node=0|zone=2) [9.576271] page_type: 0x() [9.580167] raw: 0200 ea0011774c48 ea0012ba1848 [9.588823] raw: 0001 [9.597476] page dumped because: kasan: bad access detected [9.605362] Memory state around the buggy address: [9.610714] 88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.618786] 88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.626857] >88845dd3: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.634930]^ [9.638534] 88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.646605] 88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.654675] == Cc: sta...@vger.kernel.org Signed-off-by: Qiang Zhang --- v3: - add NULL pointer check in memblock_free_late() path. v2: - add an early flag in xbc_free_mem() to free memory back to memblock in xbc_init error path or put memory to buddy allocator in normal xbc_exit. --- include/linux/bootconfig.h | 7 ++- lib/bootconfig.c | 19 +++ 2 files changed, 17 insertions(+), 9 deletions(-) diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h index e5ee2c694401..3f4b4ac527ca 100644 --- a/include/linux/bootconfig.h +++ b/include/linux/bootconfig.h @@ -288,7 +288,12 @@ int __init xbc_init(const char *buf, size_t size, const char **emsg, int *epos); int __init xbc_get_info(int *node_size, size_t *data_size); /* XBC cleanup data structures */ -void __init xbc_exit(void); +void __init _xbc_exit(bool early); + +static inline void xbc_exit(void) +{ + _xbc_exit(false); +} /* XBC embedded bootconfig data in kernel */ #ifdef CONFIG_BOOT_CONFIG_EMBED diff --git a/lib/bootconfig.c b/lib/bootconfig.c index c59d26068a64..8841554432d5 100644 --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -61,9 +61,12 @@ static inline void * __init xbc_alloc_mem(size_t size) return memblock_alloc(size, SMP_CACHE_BYTES); } -static inline void __init xbc_free_mem(void *addr, size_t size) +static inline void __init xbc_free_mem(void *addr, size_t size, bool early) { - memblock_free(addr, size); + if (early) + memblock_free(addr, size); + else if (addr) + memblock_free_late(__pa(addr), size); } #else /* !__KERNEL__ */ @@ -73,7 +76,7 @@ static inline void *xbc_alloc_mem(size_t size) return malloc(size); } -static inline void xbc_free_mem(void *addr, size_t size) +static inline void xbc_free_mem(void *addr, size_t size, bool early) { free(addr); } @@ -904,13 +907,13 @@ static int __init xbc_parse_tree(void) * If you need to r
[PATCH v2] bootconfig: use memblock_free_late to free xbc memory to buddy
From: Qiang Zhang On the time to free xbc memory in xbc_exit(), memblock may has handed over memory to buddy allocator. So it doesn't make sense to free memory back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86. Following KASAN logs shows this case. This patch fixes the xbc memory free problem by calling memblock_free() in early xbc init error rewind path and calling memblock_free_late() in xbc exit path to free memory to buddy allocator. [9.410890] == [9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260 [9.426850] Read of size 8 at addr 88845dd3 by task swapper/0/1 [9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5 [9.446403] Hardware name: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D- Dec 28 2023 [9.460789] Call Trace: [9.463518] [9.465859] dump_stack_lvl+0x53/0x70 [9.469949] print_report+0xce/0x610 [9.473944] ? __virt_addr_valid+0xf5/0x1b0 [9.478619] ? memblock_isolate_range+0x12d/0x260 [9.483877] kasan_report+0xc6/0x100 [9.487870] ? memblock_isolate_range+0x12d/0x260 [9.493125] memblock_isolate_range+0x12d/0x260 [9.498187] memblock_phys_free+0xb4/0x160 [9.502762] ? __pfx_memblock_phys_free+0x10/0x10 [9.508021] ? mutex_unlock+0x7e/0xd0 [9.512111] ? __pfx_mutex_unlock+0x10/0x10 [9.516786] ? kernel_init_freeable+0x2d4/0x430 [9.521850] ? __pfx_kernel_init+0x10/0x10 [9.526426] xbc_exit+0x17/0x70 [9.529935] kernel_init+0x38/0x1e0 [9.533829] ? _raw_spin_unlock_irq+0xd/0x30 [9.538601] ret_from_fork+0x2c/0x50 [9.542596] ? __pfx_kernel_init+0x10/0x10 [9.547170] ret_from_fork_asm+0x1a/0x30 [9.551552] [9.555649] The buggy address belongs to the physical page: [9.561875] page: refcount:0 mapcount:0 mapping: index:0x1 pfn:0x45dd30 [9.570821] flags: 0x200(node=0|zone=2) [9.576271] page_type: 0x() [9.580167] raw: 0200 ea0011774c48 ea0012ba1848 [9.588823] raw: 0001 [9.597476] page dumped because: kasan: bad access detected [9.605362] Memory state around the buggy address: [9.610714] 88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.618786] 88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.626857] >88845dd3: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.634930]^ [9.638534] 88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.646605] 88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.654675] == Cc: sta...@vger.kernel.org Signed-off-by: Qiang Zhang --- v2: - add an early flag in xbc_free_mem() to free memory back to memblock in xbc_init error path or put memory to buddy allocator in normal xbc_exit. --- include/linux/bootconfig.h | 7 ++- lib/bootconfig.c | 19 +++ 2 files changed, 17 insertions(+), 9 deletions(-) diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h index e5ee2c694401..3f4b4ac527ca 100644 --- a/include/linux/bootconfig.h +++ b/include/linux/bootconfig.h @@ -288,7 +288,12 @@ int __init xbc_init(const char *buf, size_t size, const char **emsg, int *epos); int __init xbc_get_info(int *node_size, size_t *data_size); /* XBC cleanup data structures */ -void __init xbc_exit(void); +void __init _xbc_exit(bool early); + +static inline void xbc_exit(void) +{ + _xbc_exit(false); +} /* XBC embedded bootconfig data in kernel */ #ifdef CONFIG_BOOT_CONFIG_EMBED diff --git a/lib/bootconfig.c b/lib/bootconfig.c index c59d26068a64..f9a45adc6307 100644 --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -61,9 +61,12 @@ static inline void * __init xbc_alloc_mem(size_t size) return memblock_alloc(size, SMP_CACHE_BYTES); } -static inline void __init xbc_free_mem(void *addr, size_t size) +static inline void __init xbc_free_mem(void *addr, size_t size, bool early) { - memblock_free(addr, size); + if (early) + memblock_free(addr, size); + else + memblock_free_late(__pa(addr), size); } #else /* !__KERNEL__ */ @@ -73,7 +76,7 @@ static inline void *xbc_alloc_mem(size_t size) return malloc(size); } -static inline void xbc_free_mem(void *addr, size_t size) +static inline void xbc_free_mem(void *addr, size_t size, bool early) { free(addr); } @@ -904,13 +907,13 @@ static int __init xbc_parse_tree(void) * If you need to reuse xbc_init() with new boot config, you can * use this. */ -voi
[PATCH RESEND] bootconfig: use memblock_free_late to free xbc memory to buddy
From: Qiang Zhang On the time to free xbc memory, memblock has handed over memory to buddy allocator. So it doesn't make sense to free memory back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86. Following KASAN logs shows this case. [9.410890] == [9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260 [9.426850] Read of size 8 at addr 88845dd3 by task swapper/0/1 [9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5 [9.446403] Hardware name: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D- Dec 28 2023 [9.460789] Call Trace: [9.463518] [9.465859] dump_stack_lvl+0x53/0x70 [9.469949] print_report+0xce/0x610 [9.473944] ? __virt_addr_valid+0xf5/0x1b0 [9.478619] ? memblock_isolate_range+0x12d/0x260 [9.483877] kasan_report+0xc6/0x100 [9.487870] ? memblock_isolate_range+0x12d/0x260 [9.493125] memblock_isolate_range+0x12d/0x260 [9.498187] memblock_phys_free+0xb4/0x160 [9.502762] ? __pfx_memblock_phys_free+0x10/0x10 [9.508021] ? mutex_unlock+0x7e/0xd0 [9.512111] ? __pfx_mutex_unlock+0x10/0x10 [9.516786] ? kernel_init_freeable+0x2d4/0x430 [9.521850] ? __pfx_kernel_init+0x10/0x10 [9.526426] xbc_exit+0x17/0x70 [9.529935] kernel_init+0x38/0x1e0 [9.533829] ? _raw_spin_unlock_irq+0xd/0x30 [9.538601] ret_from_fork+0x2c/0x50 [9.542596] ? __pfx_kernel_init+0x10/0x10 [9.547170] ret_from_fork_asm+0x1a/0x30 [9.551552] [9.555649] The buggy address belongs to the physical page: [9.561875] page: refcount:0 mapcount:0 mapping: index:0x1 pfn:0x45dd30 [9.570821] flags: 0x200(node=0|zone=2) [9.576271] page_type: 0x() [9.580167] raw: 0200 ea0011774c48 ea0012ba1848 [9.588823] raw: 0001 [9.597476] page dumped because: kasan: bad access detected [9.605362] Memory state around the buggy address: [9.610714] 88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.618786] 88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.626857] >88845dd3: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.634930]^ [9.638534] 88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.646605] 88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.654675] == Cc: sta...@vger.kernel.org Signed-off-by: Qiang Zhang --- lib/bootconfig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/bootconfig.c b/lib/bootconfig.c index c59d26068a64..4524ee944df0 100644 --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -63,7 +63,7 @@ static inline void * __init xbc_alloc_mem(size_t size) static inline void __init xbc_free_mem(void *addr, size_t size) { - memblock_free(addr, size); + memblock_free_late(__pa(addr), size); } #else /* !__KERNEL__ */ -- 2.39.2
[PATCH] bootconfig: use memblock_free_late to free xbc memory to buddy
From: Qiang Zhang On the time to free xbc memory, memblock has handed over memory to buddy allocator. So it doesn't make sense to free memory back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86. Following KASAN logs shows this case. [9.410890] == [9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260 [9.426850] Read of size 8 at addr 88845dd3 by task swapper/0/1 [9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5 [9.446403] Hardware name: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D- Dec 28 2023 [9.460789] Call Trace: [9.463518] [9.465859] dump_stack_lvl+0x53/0x70 [9.469949] print_report+0xce/0x610 [9.473944] ? __virt_addr_valid+0xf5/0x1b0 [9.478619] ? memblock_isolate_range+0x12d/0x260 [9.483877] kasan_report+0xc6/0x100 [9.487870] ? memblock_isolate_range+0x12d/0x260 [9.493125] memblock_isolate_range+0x12d/0x260 [9.498187] memblock_phys_free+0xb4/0x160 [9.502762] ? __pfx_memblock_phys_free+0x10/0x10 [9.508021] ? mutex_unlock+0x7e/0xd0 [9.512111] ? __pfx_mutex_unlock+0x10/0x10 [9.516786] ? kernel_init_freeable+0x2d4/0x430 [9.521850] ? __pfx_kernel_init+0x10/0x10 [9.526426] xbc_exit+0x17/0x70 [9.529935] kernel_init+0x38/0x1e0 [9.533829] ? _raw_spin_unlock_irq+0xd/0x30 [9.538601] ret_from_fork+0x2c/0x50 [9.542596] ? __pfx_kernel_init+0x10/0x10 [9.547170] ret_from_fork_asm+0x1a/0x30 [9.551552] [9.555649] The buggy address belongs to the physical page: [9.561875] page: refcount:0 mapcount:0 mapping: index:0x1 pfn:0x45dd30 [9.570821] flags: 0x200(node=0|zone=2) [9.576271] page_type: 0x() [9.580167] raw: 0200 ea0011774c48 ea0012ba1848 [9.588823] raw: 0001 [9.597476] page dumped because: kasan: bad access detected [9.605362] Memory state around the buggy address: [9.610714] 88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.618786] 88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [9.626857] >88845dd3: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.634930]^ [9.638534] 88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.646605] 88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [9.654675] == Signed-off-by: Qiang Zhang --- lib/bootconfig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/bootconfig.c b/lib/bootconfig.c index c59d26068a64..4524ee944df0 100644 --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -63,7 +63,7 @@ static inline void * __init xbc_alloc_mem(size_t size) static inline void __init xbc_free_mem(void *addr, size_t size) { - memblock_free(addr, size); + memblock_free_late(__pa(addr), size); } #else /* !__KERNEL__ */ -- 2.39.2