Hi,
This is an attempt at fixing a bug[1] uncovered by the relocation of the slab freelist pointer offset, as well as some related clean-ups.
I don't have hardware to do runtime testing, but it builds. ;)
-Kees
[1] https://bugzilla.kernel.org/show_bug.cgi?id=211537
Kees Cook (2): drm/radeon: Fix off-by-one power_state index heap overwrite drm/radeon: Avoid power table parsing memory leaks
drivers/gpu/drm/radeon/radeon_atombios.c | 26 ++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)
An out of bounds write happens when setting the default power state. KASAN sees this as:
[drm] radeon: 512M of GTT memory ready. [drm] GART: num cpu pages 131072, num gpu pages 131072 ================================================================== BUG: KASAN: slab-out-of-bounds in radeon_atombios_parse_power_table_1_3+0x1837/0x1998 [radeon] Write of size 4 at addr ffff88810178d858 by task systemd-udevd/157
CPU: 0 PID: 157 Comm: systemd-udevd Not tainted 5.12.0-E620 #50 Hardware name: eMachines eMachines E620 /Nile , BIOS V1.03 09/30/2008 Call Trace: dump_stack+0xa5/0xe6 print_address_description.constprop.0+0x18/0x239 kasan_report+0x170/0x1a8 radeon_atombios_parse_power_table_1_3+0x1837/0x1998 [radeon] radeon_atombios_get_power_modes+0x144/0x1888 [radeon] radeon_pm_init+0x1019/0x1904 [radeon] rs690_init+0x76e/0x84a [radeon] radeon_device_init+0x1c1a/0x21e5 [radeon] radeon_driver_load_kms+0xf5/0x30b [radeon] drm_dev_register+0x255/0x4a0 [drm] radeon_pci_probe+0x246/0x2f6 [radeon] pci_device_probe+0x1aa/0x294 really_probe+0x30e/0x850 driver_probe_device+0xe6/0x135 device_driver_attach+0xc1/0xf8 __driver_attach+0x13f/0x146 bus_for_each_dev+0xfa/0x146 bus_add_driver+0x2b3/0x447 driver_register+0x242/0x2c1 do_one_initcall+0x149/0x2fd do_init_module+0x1ae/0x573 load_module+0x4dee/0x5cca __do_sys_finit_module+0xf1/0x140 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae
Without KASAN, this will manifest later when the kernel attempts to allocate memory that was stomped, since it collides with the inline slab freelist pointer:
invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 PID: 781 Comm: openrc-run.sh Tainted: G W 5.10.12-gentoo-E620 #2 Hardware name: eMachines eMachines E620 /Nile , BIOS V1.03 09/30/2008 RIP: 0010:kfree+0x115/0x230 Code: 89 c5 e8 75 ea ff ff 48 8b 00 0f ba e0 09 72 63 e8 1f f4 ff ff 41 89 c4 48 8b 45 00 0f ba e0 10 72 0a 48 8b 45 08 a8 01 75 02 <0f> 0b 44 89 e1 48 c7 c2 00 f0 ff ff be 06 00 00 00 48 d3 e2 48 c7 RSP: 0018:ffffb42f40267e10 EFLAGS: 00010246 RAX: ffffd61280ee8d88 RBX: 0000000000000004 RCX: 000000008010000d RDX: 4000000000000000 RSI: ffffffffba1360b0 RDI: ffffd61280ee8d80 RBP: ffffd61280ee8d80 R08: ffffffffb91bebdf R09: 0000000000000000 R10: ffff8fe2c1047ac8 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000100 FS: 00007fe80eff6b68(0000) GS:ffff8fe339c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe80eec7bc0 CR3: 0000000038012000 CR4: 00000000000006f0 Call Trace: __free_fdtable+0x16/0x1f put_files_struct+0x81/0x9b do_exit+0x433/0x94d do_group_exit+0xa6/0xa6 __x64_sys_exit_group+0xf/0xf do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fe80ef64bea Code: Unable to access opcode bytes at RIP 0x7fe80ef64bc0. RSP: 002b:00007ffdb1c47528 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fe80ef64bea RDX: 00007fe80ef64f60 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 00007fe80ee2c620 R11: 0000000000000246 R12: 00007fe80eff41e0 R13: 00000000ffffffff R14: 0000000000000024 R15: 00007fe80edf9cd0 Modules linked in: radeon(+) ath5k(+) snd_hda_codec_realtek ...
Use a valid power_state index when initializing the "flags" and "misc" and "misc2" fields.
Reported-by: Erhard F. erhard_f@mailbox.org Fixes: a48b9b4edb8b ("drm/radeon/kms/pm: add asic specific callbacks for getting power state (v2)") Fixes: 79daedc94281 ("drm/radeon/kms: minor pm cleanups") Signed-off-by: Kees Cook keescook@chromium.org --- drivers/gpu/drm/radeon/radeon_atombios.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c index 42301b4e56f5..f9f4efa1738c 100644 --- a/drivers/gpu/drm/radeon/radeon_atombios.c +++ b/drivers/gpu/drm/radeon/radeon_atombios.c @@ -2250,10 +2250,10 @@ static int radeon_atombios_parse_power_table_1_3(struct radeon_device *rdev) rdev->pm.default_power_state_index = state_index - 1; rdev->pm.power_state[state_index - 1].default_clock_mode = &rdev->pm.power_state[state_index - 1].clock_info[0]; - rdev->pm.power_state[state_index].flags &= + rdev->pm.power_state[state_index - 1].flags &= ~RADEON_PM_STATE_SINGLE_DISPLAY_ONLY; - rdev->pm.power_state[state_index].misc = 0; - rdev->pm.power_state[state_index].misc2 = 0; + rdev->pm.power_state[state_index - 1].misc = 0; + rdev->pm.power_state[state_index - 1].misc2 = 0; } return state_index; }
Avoid leaving a hanging pre-allocated clock_info if last mode is invalid, and avoid heap corruption if no valid modes are found.
Fixes: 6991b8f2a319 ("drm/radeon/kms: fix segfault in pm rework") Signed-off-by: Kees Cook keescook@chromium.org --- drivers/gpu/drm/radeon/radeon_atombios.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c index f9f4efa1738c..28c4413f4dc8 100644 --- a/drivers/gpu/drm/radeon/radeon_atombios.c +++ b/drivers/gpu/drm/radeon/radeon_atombios.c @@ -2120,11 +2120,14 @@ static int radeon_atombios_parse_power_table_1_3(struct radeon_device *rdev) return state_index; /* last mode is usually default, array is low to high */ for (i = 0; i < num_modes; i++) { - rdev->pm.power_state[state_index].clock_info = - kcalloc(1, sizeof(struct radeon_pm_clock_info), - GFP_KERNEL); + /* avoid memory leaks from invalid modes or unknown frev. */ + if (!rdev->pm.power_state[state_index].clock_info) { + rdev->pm.power_state[state_index].clock_info = + kzalloc(sizeof(struct radeon_pm_clock_info), + GFP_KERNEL); + } if (!rdev->pm.power_state[state_index].clock_info) - return state_index; + goto out; rdev->pm.power_state[state_index].num_clock_modes = 1; rdev->pm.power_state[state_index].clock_info[0].voltage.type = VOLTAGE_NONE; switch (frev) { @@ -2243,8 +2246,15 @@ static int radeon_atombios_parse_power_table_1_3(struct radeon_device *rdev) break; } } +out: + /* free any unused clock_info allocation. */ + if (state_index && state_index < num_modes) { + kfree(rdev->pm.power_state[state_index].clock_info); + rdev->pm.power_state[state_index].clock_info = NULL; + } + /* last mode is usually default */ - if (rdev->pm.default_power_state_index == -1) { + if (state_index && rdev->pm.default_power_state_index == -1) { rdev->pm.power_state[state_index - 1].type = POWER_STATE_TYPE_DEFAULT; rdev->pm.default_power_state_index = state_index - 1;
On Mon, May 3, 2021 at 1:06 AM Kees Cook keescook@chromium.org wrote:
Hi,
This is an attempt at fixing a bug[1] uncovered by the relocation of the slab freelist pointer offset, as well as some related clean-ups.
I don't have hardware to do runtime testing, but it builds. ;)
-Kees
[1] https://bugzilla.kernel.org/show_bug.cgi?id=211537
Kees Cook (2): drm/radeon: Fix off-by-one power_state index heap overwrite drm/radeon: Avoid power table parsing memory leaks
Applied. Thanks!
Alex
drivers/gpu/drm/radeon/radeon_atombios.c | 26 ++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)
-- 2.25.1
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