Divide By Zero

In the Linux kernel, the following vulnerability has been resolved: fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod() In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000, cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It's then passed to fb_cvt_hperiod(), where it's used as a divider -- division by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to avoid such overflow... Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool.Show less

In the Linux kernel, the following vulnerability has been resolved: PM: EM: Fix potential division-by-zero error in em_compute_costs() When the device is of a non-CPU type, table[i].performance won't be initialized in the previous em_init_performance(), resulting in division by zero when calculating costs in em_compute_costs(). Since the 'cost' algorithm is only used for EAS energy efficiency calculations and is currently not utilized by other device drivers, we should add the _is_cpu_device(dev) check to prevent this division-by-zero issue.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid divide by zero by initializing dummy pitch to 1 [Why] If the dummy values in `populate_dummy_dml_surface_cfg()` aren't updated then they can lead to a divide by zero in downstream callers like CalculateVMAndRowBytes() [How] Initialize dummy value to a value to avoid divide by zero.Show less

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: make sure that ptp_rate is not 0 before configuring timestamping The stmmac platform drivers that do not open-code the clk_ptp_rate value after having retrieved the default one from the device-tree can end up with 0 in clk_ptp_rate (as clk_get_rate can return 0). It will eventually propagate up to PTP initialization when bringing up the interface, leading to a divide by 0: Division by zero in kernel. CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.30-00001-g48313bd5768a #22 Hardware name: STM32 (Device Tree Support) Call trace: unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x6c/0x8c dump_stack_lvl from Ldiv0_64+0x8/0x18 Ldiv0_64 from stmmac_init_tstamp_counter+0x190/0x1a4 stmmac_init_tstamp_counter from stmmac_hw_setup+0xc1c/0x111c stmmac_hw_setup from __stmmac_open+0x18c/0x434 __stmmac_open from stmmac_open+0x3c/0xbc stmmac_open from __dev_open+0xf4/0x1ac __dev_open from __dev_change_flags+0x1cc/0x224 __dev_change_flags from dev_change_flags+0x24/0x60 dev_change_flags from ip_auto_config+0x2e8/0x11a0 ip_auto_config from do_one_initcall+0x84/0x33c do_one_initcall from kernel_init_freeable+0x1b8/0x214 kernel_init_freeable from kernel_init+0x24/0x140 kernel_init from ret_from_fork+0x14/0x28 Exception stack(0xe0815fb0 to 0xe0815ff8) Prevent this division by 0 by adding an explicit check and error log about the actual issue. While at it, remove the same check from stmmac_ptp_register, which then becomes duplicateShow less

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw89: 8852a: rfk: fix div 0 exception The DPK is a kind of RF calibration whose algorithm is to fine tune parameters and calibrate, and check the result. If the result isn't good enough, it could adjust parameters and try again. This issue is to read and show the result, but it could be a negative calibration result that causes divisor 0 and core dump. So, fix it by phy_div() that does division only if divisor isn't zero; otherwise, zero is adopted. divide error: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 728 Comm: wpa_supplicant Not tainted 5.10.114-16019-g462a1661811a #1 <HASH:d024 28> RIP: 0010:rtw8852a_dpk+0x14ae/0x288f [rtw89_core] RSP: 0018:ffffa9bb412a7520 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000000180fc RDI: ffffa141d01023c0 RBP: ffffa9bb412a76a0 R08: 0000000000001319 R09: 00000000ffffff92 R10: ffffffffc0292de3 R11: ffffffffc00d2f51 R12: 0000000000000000 R13: ffffa141d01023c0 R14: ffffffffc0290250 R15: ffffa141d0102638 FS: 00007fa99f5c2740(0000) GS:ffffa142e5e80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000013e8e010 CR3: 0000000110d2c000 CR4: 0000000000750ee0 PKRU: 55555554 Call Trace: rtw89_core_sta_add+0x95/0x9c [rtw89_core <HASH:d239 29>] rtw89_ops_sta_state+0x5d/0x108 [rtw89_core <HASH:d239 29>] drv_sta_state+0x115/0x66f [mac80211 <HASH:81fe 30>] sta_info_insert_rcu+0x45c/0x713 [mac80211 <HASH:81fe 30>] sta_info_insert+0xf/0x1b [mac80211 <HASH:81fe 30>] ieee80211_prep_connection+0x9d6/0xb0c [mac80211 <HASH:81fe 30>] ieee80211_mgd_auth+0x2aa/0x352 [mac80211 <HASH:81fe 30>] cfg80211_mlme_auth+0x160/0x1f6 [cfg80211 <HASH:00cd 31>] nl80211_authenticate+0x2e5/0x306 [cfg80211 <HASH:00cd 31>] genl_rcv_msg+0x371/0x3a1 ? nl80211_stop_sched_scan+0xe5/0xe5 [cfg80211 <HASH:00cd 31>] ? genl_rcv+0x36/0x36 netlink_rcv_skb+0x8a/0xf9 genl_rcv+0x28/0x36 netlink_unicast+0x27b/0x3a0 netlink_sendmsg+0x2aa/0x469 sock_sendmsg_nosec+0x49/0x4d ____sys_sendmsg+0xe5/0x213 __sys_sendmsg+0xec/0x157 ? syscall_enter_from_user_mode+0xd7/0x116 do_syscall_64+0x43/0x55 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fa99f6e689bShow less

In the Linux kernel, the following vulnerability has been resolved: video: fbdev: arkfb: Fix a divide-by-zero bug in ark_set_pixclock() Since the user can control the arguments of the ioctl() from the user space, under special arguments that may result in a divide-by-zero bug in: drivers/video/fbdev/arkfb.c:784: ark_set_pixclock(info, (hdiv * info->var.pixclock) / hmul); with hdiv=1, pixclock=1 and hmul=2 you end up with (1*1)/2 = (int) 0. and then in: drivers/video/fbdev/arkfb.c:504: rv = dac_set_freq(par->dac, 0, 1000000000 / pixclock); we'll get a division-by-zero. The following log can reveal it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:ark_set_pixclock drivers/video/fbdev/arkfb.c:504 [inline] RIP: 0010:arkfb_set_par+0x10fc/0x24c0 drivers/video/fbdev/arkfb.c:784 Call Trace: fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189 Fix this by checking the argument of ark_set_pixclock() first.Show less

In the Linux kernel, the following vulnerability has been resolved: video: fbdev: i740fb: Check the argument of i740_calc_vclk() Since the user can control the arguments of the ioctl() from the user space, under special arguments that may result in a divide-by-zero bug. If the user provides an improper 'pixclock' value that makes the argumet of i740_calc_vclk() less than 'I740_RFREQ_FIX', it will cause a divide-by-zero bug in: drivers/video/fbdev/i740fb.c:353 p_best = min(15, ilog2(I740_MAX_VCO_FREQ / (freq / I740_RFREQ_FIX))); The following log can reveal it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:i740_calc_vclk drivers/video/fbdev/i740fb.c:353 [inline] RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:646 [inline] RIP: 0010:i740fb_set_par+0x163f/0x3b70 drivers/video/fbdev/i740fb.c:742 Call Trace: fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189 Fix this by checking the argument of i740_calc_vclk() first.Show less

In the Linux kernel, the following vulnerability has been resolved: fbdev: fb_pm2fb: Avoid potential divide by zero error In `do_fb_ioctl()` of fbmem.c, if cmd is FBIOPUT_VSCREENINFO, var will be copied from user, then go through `fb_set_var()` and `info->fbops->fb_check_var()` which could may be `pm2fb_check_var()`. Along the path, `var->pixclock` won't be modified. This function checks whether reciprocal of `var->pixclock` is too high. If `var->pixclock` is zero, there will be a divide by zero error. So, it is necessary to check whether denominator is zero to avoid crash. As this bug is found by Syzkaller, logs are listed below. divide error in pm2fb_check_var Call Trace: <TASK> fb_set_var+0x367/0xeb0 drivers/video/fbdev/core/fbmem.c:1015 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189Show less

In the Linux kernel, the following vulnerability has been resolved: objtool, media: dib8000: Prevent divide-by-zero in dib8000_set_dds() If dib8000_set_dds()'s call to dib8000_read32() returns zero, the result is a divide-by-zero. Prevent that from happening. Fixes the following warning with an UBSAN kernel: drivers/media/dvb-frontends/dib8000.o: warning: objtool: dib8000_tune() falls through to next function dib8096p_cfg_DibRx()Show less

In the Linux kernel, the following vulnerability has been resolved: spi: spi-mem: Add fix to avoid divide error For some SPI flash memory operations, dummy bytes are not mandatory. For example, in Winbond SPINAND flash memory devices, the `write_cache` and `update_cache` operation variants have zero dummy bytes. Calculating the duration for SPI memory operations with zero dummy bytes causes a divide error when `ncycles` is calculated in the spi_mem_calc_op_duration(). Add changes to skip the 'ncylcles' calculation for zero dummy bytes. Following divide error is fixed by this change: Oops: divide error: 0000 [#1] PREEMPT SMP NOPTI ... ? do_trap+0xdb/0x100 ? do_error_trap+0x75/0xb0 ? spi_mem_calc_op_duration+0x56/0xb0 ? exc_divide_error+0x3b/0x70 ? spi_mem_calc_op_duration+0x56/0xb0 ? asm_exc_divide_error+0x1b/0x20 ? spi_mem_calc_op_duration+0x56/0xb0 ? spinand_select_op_variant+0xee/0x190 [spinand] spinand_match_and_init+0x13e/0x1a0 [spinand] spinand_manufacturer_match+0x6e/0xa0 [spinand] spinand_probe+0x357/0x7f0 [spinand] ? kernfs_activate+0x87/0xd0 spi_mem_probe+0x7a/0xb0 spi_probe+0x7d/0x130Show less

In the Linux kernel, the following vulnerability has been resolved: pwm: mediatek: Prevent divide-by-zero in pwm_mediatek_config() With CONFIG_COMPILE_TEST && !CONFIG_HAVE_CLK, pwm_mediatek_config() has a divide-by-zero in the following line: do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm])); due to the fact that the !CONFIG_HAVE_CLK version of clk_get_rate() returns zero. This is presumably just a theoretical problem: COMPILE_TEST overrides the dependency on RALINK which would select COMMON_CLK. Regardless it's a good idea to check for the error explicitly to avoid divide-by-zero. Fixes the following warning: drivers/pwm/pwm-mediatek.o: warning: objtool: .text: unexpected end of section [ukleinek: s/CONFIG_CLK/CONFIG_HAVE_CLK/]Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm: Prevent division by zero The user can set any speed value. If speed is greater than UINT_MAX/8, division by zero is possible. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm: Prevent division by zero The user can set any speed value. If speed is greater than UINT_MAX/8, division by zero is possible. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm/smu11: Prevent division by zero The user can set any speed value. If speed is greater than UINT_MAX/8, division by zero is possible. Found by Linux Verification Center (linuxtesting.org) with SVACE. (cherry picked from commit da7dc714a8f8e1c9fc33c57cd63583779a3bef71)Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm: Prevent division by zero The user can set any speed value. If speed is greater than UINT_MAX/8, division by zero is possible. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm: Prevent division by zero The user can set any speed value. If speed is greater than UINT_MAX/8, division by zero is possible. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm: Prevent division by zero The user can set any speed value. If speed is greater than UINT_MAX/8, division by zero is possible. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less