| Message ID | 20240625174607.13821-1-bethany.jamison@canonical.com |
|---|---|
| Headers | show |
| Series | CVE-2024-35997 | expand |
On 25-06-2024 19:46, Bethany Jamison wrote: > [Impact] > > HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up > > The flag I2C_HID_READ_PENDING is used to serialize I2C operations. > However, this is not necessary, because I2C core already has its own > locking for that. > > More importantly, this flag can cause a lock-up: if the flag is set in > i2c_hid_xfer() and an interrupt happens, the interrupt handler > (i2c_hid_irq) will check this flag and return immediately without doing > anything, then the interrupt handler will be invoked again in an > infinite loop. > > Since interrupt handler is an RT task, it takes over the CPU and the > flag-clearing task never gets scheduled, thus we have a lock-up. > > Delete this unnecessary flag. > > [Fix] > > Noble: Clean cherry-pick from linux-6.8.y > Jammy: pending > Focal: pending > Bionic: fix sent to esm ML > Xenial: fix sent to esm ML > Trusty: not going to be fixed by us > > [Test Case] > > Compile and boot tested. > > [Where problems could occur] > > This fix affects those who use the HID over I2C protocol > implementation, an issue with this fix would be visible to the user > via a system freeze or crash. > > Nam Cao (1): > HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up > > drivers/hid/i2c-hid/i2c-hid-core.c | 9 --------- > 1 file changed, 9 deletions(-) > Acked-by: Thibault Ferrante <thibault.ferrante@canonical.com> -- Thibault
On Tue, Jun 25, 2024 at 12:46:06PM -0500, Bethany Jamison wrote: > [Impact] > > HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up > > The flag I2C_HID_READ_PENDING is used to serialize I2C operations. > However, this is not necessary, because I2C core already has its own > locking for that. > > More importantly, this flag can cause a lock-up: if the flag is set in > i2c_hid_xfer() and an interrupt happens, the interrupt handler > (i2c_hid_irq) will check this flag and return immediately without doing > anything, then the interrupt handler will be invoked again in an > infinite loop. > > Since interrupt handler is an RT task, it takes over the CPU and the > flag-clearing task never gets scheduled, thus we have a lock-up. > > Delete this unnecessary flag. > > [Fix] > > Noble: Clean cherry-pick from linux-6.8.y > Jammy: pending > Focal: pending > Bionic: fix sent to esm ML > Xenial: fix sent to esm ML > Trusty: not going to be fixed by us > > [Test Case] > > Compile and boot tested. > > [Where problems could occur] > > This fix affects those who use the HID over I2C protocol > implementation, an issue with this fix would be visible to the user > via a system freeze or crash. > > Nam Cao (1): > HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up > > drivers/hid/i2c-hid/i2c-hid-core.c | 9 --------- > 1 file changed, 9 deletions(-) > > -- > 2.34.1 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team Acked-by: Manuel Diewald <manuel.diewald@canonical.com>
On 25.06.24 19:46, Bethany Jamison wrote: > [Impact] > > HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up > > The flag I2C_HID_READ_PENDING is used to serialize I2C operations. > However, this is not necessary, because I2C core already has its own > locking for that. > > More importantly, this flag can cause a lock-up: if the flag is set in > i2c_hid_xfer() and an interrupt happens, the interrupt handler > (i2c_hid_irq) will check this flag and return immediately without doing > anything, then the interrupt handler will be invoked again in an > infinite loop. > > Since interrupt handler is an RT task, it takes over the CPU and the > flag-clearing task never gets scheduled, thus we have a lock-up. > > Delete this unnecessary flag. > > [Fix] > > Noble: Clean cherry-pick from linux-6.8.y > Jammy: pending > Focal: pending > Bionic: fix sent to esm ML > Xenial: fix sent to esm ML > Trusty: not going to be fixed by us > > [Test Case] > > Compile and boot tested. > > [Where problems could occur] > > This fix affects those who use the HID over I2C protocol > implementation, an issue with this fix would be visible to the user > via a system freeze or crash. > > Nam Cao (1): > HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up > > drivers/hid/i2c-hid/i2c-hid-core.c | 9 --------- > 1 file changed, 9 deletions(-) > Rejected for the following reasons: Already applied for Noble update: v6.8.9 upstream stable release. CVE number added to commit message. -Stefan