| Message ID | 20240811150229.82321-1-alexghiti@rivosinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [-fixes] riscv: Fix out-of-bounds when accessing Andes per hart vendor extension array | expand |
On Sun, Aug 11, 2024 at 05:02:29PM +0200, Alexandre Ghiti wrote: > The out-of-bounds access is reported by UBSAN: > > [ 0.000000] UBSAN: array-index-out-of-bounds in ../arch/riscv/kernel/vendor_extensions.c:41:66 > [ 0.000000] index -1 is out of range for type 'riscv_isavendorinfo [32]' > [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.11.0-rc2ubuntu-defconfig #2 > [ 0.000000] Hardware name: riscv-virtio,qemu (DT) > [ 0.000000] Call Trace: > [ 0.000000] [<ffffffff94e078ba>] dump_backtrace+0x32/0x40 > [ 0.000000] [<ffffffff95c83c1a>] show_stack+0x38/0x44 > [ 0.000000] [<ffffffff95c94614>] dump_stack_lvl+0x70/0x9c > [ 0.000000] [<ffffffff95c94658>] dump_stack+0x18/0x20 > [ 0.000000] [<ffffffff95c8bbb2>] ubsan_epilogue+0x10/0x46 > [ 0.000000] [<ffffffff95485a82>] __ubsan_handle_out_of_bounds+0x94/0x9c > [ 0.000000] [<ffffffff94e09442>] __riscv_isa_vendor_extension_available+0x90/0x92 > [ 0.000000] [<ffffffff94e043b6>] riscv_cpufeature_patch_func+0xc4/0x148 > [ 0.000000] [<ffffffff94e035f8>] _apply_alternatives+0x42/0x50 > [ 0.000000] [<ffffffff95e04196>] apply_boot_alternatives+0x3c/0x100 > [ 0.000000] [<ffffffff95e05b52>] setup_arch+0x85a/0x8bc > [ 0.000000] [<ffffffff95e00ca0>] start_kernel+0xa4/0xfb6 > > This happens because we unconditionally use the cpu parameter to access > this array. But if -1 is passed, that means we should not and we don't > need to access this array, so simply prevent accessing the array in that case. > > Fixes: 23c996fc2bc1 ("riscv: Extend cpufeature.c to detect vendor extensions") > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Tested-by: Conor Dooley <conor.dooley@microchip.com>
On Sun, Aug 11, 2024 at 05:02:29PM +0200, Alexandre Ghiti wrote: > The out-of-bounds access is reported by UBSAN: > > [ 0.000000] UBSAN: array-index-out-of-bounds in ../arch/riscv/kernel/vendor_extensions.c:41:66 > [ 0.000000] index -1 is out of range for type 'riscv_isavendorinfo [32]' > [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.11.0-rc2ubuntu-defconfig #2 > [ 0.000000] Hardware name: riscv-virtio,qemu (DT) > [ 0.000000] Call Trace: > [ 0.000000] [<ffffffff94e078ba>] dump_backtrace+0x32/0x40 > [ 0.000000] [<ffffffff95c83c1a>] show_stack+0x38/0x44 > [ 0.000000] [<ffffffff95c94614>] dump_stack_lvl+0x70/0x9c > [ 0.000000] [<ffffffff95c94658>] dump_stack+0x18/0x20 > [ 0.000000] [<ffffffff95c8bbb2>] ubsan_epilogue+0x10/0x46 > [ 0.000000] [<ffffffff95485a82>] __ubsan_handle_out_of_bounds+0x94/0x9c > [ 0.000000] [<ffffffff94e09442>] __riscv_isa_vendor_extension_available+0x90/0x92 > [ 0.000000] [<ffffffff94e043b6>] riscv_cpufeature_patch_func+0xc4/0x148 > [ 0.000000] [<ffffffff94e035f8>] _apply_alternatives+0x42/0x50 > [ 0.000000] [<ffffffff95e04196>] apply_boot_alternatives+0x3c/0x100 > [ 0.000000] [<ffffffff95e05b52>] setup_arch+0x85a/0x8bc > [ 0.000000] [<ffffffff95e00ca0>] start_kernel+0xa4/0xfb6 > > This happens because we unconditionally use the cpu parameter to access > this array. But if -1 is passed, that means we should not and we don't > need to access this array, so simply prevent accessing the array in that case. > > Fixes: 23c996fc2bc1 ("riscv: Extend cpufeature.c to detect vendor extensions") > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> > --- > arch/riscv/kernel/vendor_extensions.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c > index b6c1e7b5d34b..01dc79b1d17b 100644 > --- a/arch/riscv/kernel/vendor_extensions.c > +++ b/arch/riscv/kernel/vendor_extensions.c > @@ -27,7 +27,7 @@ const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_li > * @bit: bit position of the desired extension > * Return: true or false > * > - * NOTE: When cpu is -1, will check if extension is available on all cpus > + * NOTE: When cpu is VENDOR_EXT_ALL_CPUS, will check if extension is available on all cpus > */ > bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit) > { > @@ -38,14 +38,15 @@ bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsig > #ifdef CONFIG_RISCV_ISA_VENDOR_EXT_ANDES > case ANDES_VENDOR_ID: > bmap = &riscv_isa_vendor_ext_list_andes.all_harts_isa_bitmap; > - cpu_bmap = &riscv_isa_vendor_ext_list_andes.per_hart_isa_bitmap[cpu]; > + if (cpu != VENDOR_EXT_ALL_CPUS) > + cpu_bmap = &riscv_isa_vendor_ext_list_andes.per_hart_isa_bitmap[cpu]; > break; > #endif > default: > return false; > } > > - if (cpu != -1) > + if (cpu != VENDOR_EXT_ALL_CPUS) > bmap = &cpu_bmap[cpu]; > > if (bit >= RISCV_ISA_VENDOR_EXT_MAX) > -- > 2.39.2 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv The line that is setting the cpu_bmap shouldn't be indexing into it at all. It is supposed to be: cpu_bmap = &riscv_isa_vendor_ext_list_andes.per_hart_isa_bitmap; The indexing is handled later on by the if-statement. Thank you for looking into this. - Charlie
diff --git a/arch/riscv/kernel/vendor_extensions.c b/arch/riscv/kernel/vendor_extensions.c index b6c1e7b5d34b..01dc79b1d17b 100644 --- a/arch/riscv/kernel/vendor_extensions.c +++ b/arch/riscv/kernel/vendor_extensions.c @@ -27,7 +27,7 @@ const size_t riscv_isa_vendor_ext_list_size = ARRAY_SIZE(riscv_isa_vendor_ext_li * @bit: bit position of the desired extension * Return: true or false * - * NOTE: When cpu is -1, will check if extension is available on all cpus + * NOTE: When cpu is VENDOR_EXT_ALL_CPUS, will check if extension is available on all cpus */ bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsigned int bit) { @@ -38,14 +38,15 @@ bool __riscv_isa_vendor_extension_available(int cpu, unsigned long vendor, unsig #ifdef CONFIG_RISCV_ISA_VENDOR_EXT_ANDES case ANDES_VENDOR_ID: bmap = &riscv_isa_vendor_ext_list_andes.all_harts_isa_bitmap; - cpu_bmap = &riscv_isa_vendor_ext_list_andes.per_hart_isa_bitmap[cpu]; + if (cpu != VENDOR_EXT_ALL_CPUS) + cpu_bmap = &riscv_isa_vendor_ext_list_andes.per_hart_isa_bitmap[cpu]; break; #endif default: return false; } - if (cpu != -1) + if (cpu != VENDOR_EXT_ALL_CPUS) bmap = &cpu_bmap[cpu]; if (bit >= RISCV_ISA_VENDOR_EXT_MAX)
The out-of-bounds access is reported by UBSAN: [ 0.000000] UBSAN: array-index-out-of-bounds in ../arch/riscv/kernel/vendor_extensions.c:41:66 [ 0.000000] index -1 is out of range for type 'riscv_isavendorinfo [32]' [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.11.0-rc2ubuntu-defconfig #2 [ 0.000000] Hardware name: riscv-virtio,qemu (DT) [ 0.000000] Call Trace: [ 0.000000] [<ffffffff94e078ba>] dump_backtrace+0x32/0x40 [ 0.000000] [<ffffffff95c83c1a>] show_stack+0x38/0x44 [ 0.000000] [<ffffffff95c94614>] dump_stack_lvl+0x70/0x9c [ 0.000000] [<ffffffff95c94658>] dump_stack+0x18/0x20 [ 0.000000] [<ffffffff95c8bbb2>] ubsan_epilogue+0x10/0x46 [ 0.000000] [<ffffffff95485a82>] __ubsan_handle_out_of_bounds+0x94/0x9c [ 0.000000] [<ffffffff94e09442>] __riscv_isa_vendor_extension_available+0x90/0x92 [ 0.000000] [<ffffffff94e043b6>] riscv_cpufeature_patch_func+0xc4/0x148 [ 0.000000] [<ffffffff94e035f8>] _apply_alternatives+0x42/0x50 [ 0.000000] [<ffffffff95e04196>] apply_boot_alternatives+0x3c/0x100 [ 0.000000] [<ffffffff95e05b52>] setup_arch+0x85a/0x8bc [ 0.000000] [<ffffffff95e00ca0>] start_kernel+0xa4/0xfb6 This happens because we unconditionally use the cpu parameter to access this array. But if -1 is passed, that means we should not and we don't need to access this array, so simply prevent accessing the array in that case. Fixes: 23c996fc2bc1 ("riscv: Extend cpufeature.c to detect vendor extensions") Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- arch/riscv/kernel/vendor_extensions.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)