To quote from the kernel documentation:
Historically the kernel has allowed TIOCSTI, which will push characters into a controlling TTY. This continues to be used as a malicious privilege escalation mechanism, and provides no meaningful real-world utility any more. Its use is considered a dangerous legacy operation, and can be disabled on most systems.
Say Y here only if you have confirmed that your system's userspace depends on this functionality to continue operating normally.
Processes which run with CAP_SYS_ADMIN, such as BRLTTY, can use TIOCSTI even when this is set to N.
This functionality can be changed at runtime with the dev.tty.legacy_tiocsti sysctl. This configuration option sets the default value of the sysctl.
This patch therefore proposes to no longer allow legacy TIOCSTI usage in IPFire, given its security implications and the apparent lack of legitimate usage.
Signed-off-by: Peter Müller peter.mueller@ipfire.org --- config/kernel/kernel.config.aarch64-ipfire | 2 +- config/kernel/kernel.config.riscv64-ipfire | 2 +- config/kernel/kernel.config.x86_64-ipfire | 2 +- config/rootfiles/common/aarch64/linux | 1 - config/rootfiles/common/riscv64/linux | 1 - config/rootfiles/common/x86_64/linux | 1 - 6 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/config/kernel/kernel.config.aarch64-ipfire b/config/kernel/kernel.config.aarch64-ipfire index 4770ed828..9b8bfa559 100644 --- a/config/kernel/kernel.config.aarch64-ipfire +++ b/config/kernel/kernel.config.aarch64-ipfire @@ -3575,7 +3575,7 @@ CONFIG_HW_CONSOLE=y CONFIG_VT_HW_CONSOLE_BINDING=y CONFIG_UNIX98_PTYS=y # CONFIG_LEGACY_PTYS is not set -CONFIG_LEGACY_TIOCSTI=y +# CONFIG_LEGACY_TIOCSTI is not set # CONFIG_LDISC_AUTOLOAD is not set
# diff --git a/config/kernel/kernel.config.riscv64-ipfire b/config/kernel/kernel.config.riscv64-ipfire index fb4ec14d5..44d89c99e 100644 --- a/config/kernel/kernel.config.riscv64-ipfire +++ b/config/kernel/kernel.config.riscv64-ipfire @@ -3249,7 +3249,7 @@ CONFIG_HW_CONSOLE=y CONFIG_VT_HW_CONSOLE_BINDING=y CONFIG_UNIX98_PTYS=y # CONFIG_LEGACY_PTYS is not set -CONFIG_LEGACY_TIOCSTI=y +# CONFIG_LEGACY_TIOCSTI is not set # CONFIG_LDISC_AUTOLOAD is not set
# diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kernel.config.x86_64-ipfire index 2a2748ea4..41d6f0635 100644 --- a/config/kernel/kernel.config.x86_64-ipfire +++ b/config/kernel/kernel.config.x86_64-ipfire @@ -3497,7 +3497,7 @@ CONFIG_HW_CONSOLE=y CONFIG_VT_HW_CONSOLE_BINDING=y CONFIG_UNIX98_PTYS=y # CONFIG_LEGACY_PTYS is not set -CONFIG_LEGACY_TIOCSTI=y +# CONFIG_LEGACY_TIOCSTI is not set # CONFIG_LDISC_AUTOLOAD is not set
# diff --git a/config/rootfiles/common/aarch64/linux b/config/rootfiles/common/aarch64/linux index 5d2d36a46..a32c3770e 100644 --- a/config/rootfiles/common/aarch64/linux +++ b/config/rootfiles/common/aarch64/linux @@ -9185,7 +9185,6 @@ etc/modprobe.d/ipv6.conf #lib/modules/KVER-ipfire/build/include/config/LEDS_TRIGGER_TTY #lib/modules/KVER-ipfire/build/include/config/LED_TRIGGER_PHY #lib/modules/KVER-ipfire/build/include/config/LEGACY_DIRECT_IO -#lib/modules/KVER-ipfire/build/include/config/LEGACY_TIOCSTI #lib/modules/KVER-ipfire/build/include/config/LIB80211 #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_CCMP #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_TKIP diff --git a/config/rootfiles/common/riscv64/linux b/config/rootfiles/common/riscv64/linux index c2e0191af..5e1ac921c 100644 --- a/config/rootfiles/common/riscv64/linux +++ b/config/rootfiles/common/riscv64/linux @@ -8345,7 +8345,6 @@ etc/modprobe.d/ipv6.conf #lib/modules/KVER-ipfire/build/include/config/LEDS_USER #lib/modules/KVER-ipfire/build/include/config/LED_TRIGGER_PHY #lib/modules/KVER-ipfire/build/include/config/LEGACY_DIRECT_IO -#lib/modules/KVER-ipfire/build/include/config/LEGACY_TIOCSTI #lib/modules/KVER-ipfire/build/include/config/LIB80211 #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_CCMP #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_TKIP diff --git a/config/rootfiles/common/x86_64/linux b/config/rootfiles/common/x86_64/linux index a51f3487f..f3a8dea19 100644 --- a/config/rootfiles/common/x86_64/linux +++ b/config/rootfiles/common/x86_64/linux @@ -8996,7 +8996,6 @@ etc/modprobe.d/ipv6.conf #lib/modules/KVER-ipfire/build/include/config/LEDS_USER #lib/modules/KVER-ipfire/build/include/config/LED_TRIGGER_PHY #lib/modules/KVER-ipfire/build/include/config/LEGACY_DIRECT_IO -#lib/modules/KVER-ipfire/build/include/config/LEGACY_TIOCSTI #lib/modules/KVER-ipfire/build/include/config/LEGACY_VSYSCALL_NONE #lib/modules/KVER-ipfire/build/include/config/LIB80211 #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_CCMP
Signed-off-by: Michael Tremer michael.tremer@ipfire.org
On 14 Jan 2024, at 15:59, Peter Müller peter.mueller@ipfire.org wrote:
To quote from the kernel documentation:
Historically the kernel has allowed TIOCSTI, which will push characters into a controlling TTY. This continues to be used as a malicious privilege escalation mechanism, and provides no meaningful real-world utility any more. Its use is considered a dangerous legacy operation, and can be disabled on most systems.
Say Y here only if you have confirmed that your system's userspace depends on this functionality to continue operating normally.
Processes which run with CAP_SYS_ADMIN, such as BRLTTY, can use TIOCSTI even when this is set to N.
This functionality can be changed at runtime with the dev.tty.legacy_tiocsti sysctl. This configuration option sets the default value of the sysctl.
This patch therefore proposes to no longer allow legacy TIOCSTI usage in IPFire, given its security implications and the apparent lack of legitimate usage.
Signed-off-by: Peter Müller peter.mueller@ipfire.org
config/kernel/kernel.config.aarch64-ipfire | 2 +- config/kernel/kernel.config.riscv64-ipfire | 2 +- config/kernel/kernel.config.x86_64-ipfire | 2 +- config/rootfiles/common/aarch64/linux | 1 - config/rootfiles/common/riscv64/linux | 1 - config/rootfiles/common/x86_64/linux | 1 - 6 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/config/kernel/kernel.config.aarch64-ipfire b/config/kernel/kernel.config.aarch64-ipfire index 4770ed828..9b8bfa559 100644 --- a/config/kernel/kernel.config.aarch64-ipfire +++ b/config/kernel/kernel.config.aarch64-ipfire @@ -3575,7 +3575,7 @@ CONFIG_HW_CONSOLE=y CONFIG_VT_HW_CONSOLE_BINDING=y CONFIG_UNIX98_PTYS=y # CONFIG_LEGACY_PTYS is not set -CONFIG_LEGACY_TIOCSTI=y +# CONFIG_LEGACY_TIOCSTI is not set # CONFIG_LDISC_AUTOLOAD is not set
# diff --git a/config/kernel/kernel.config.riscv64-ipfire b/config/kernel/kernel.config.riscv64-ipfire index fb4ec14d5..44d89c99e 100644 --- a/config/kernel/kernel.config.riscv64-ipfire +++ b/config/kernel/kernel.config.riscv64-ipfire @@ -3249,7 +3249,7 @@ CONFIG_HW_CONSOLE=y CONFIG_VT_HW_CONSOLE_BINDING=y CONFIG_UNIX98_PTYS=y # CONFIG_LEGACY_PTYS is not set -CONFIG_LEGACY_TIOCSTI=y +# CONFIG_LEGACY_TIOCSTI is not set # CONFIG_LDISC_AUTOLOAD is not set
# diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kernel.config.x86_64-ipfire index 2a2748ea4..41d6f0635 100644 --- a/config/kernel/kernel.config.x86_64-ipfire +++ b/config/kernel/kernel.config.x86_64-ipfire @@ -3497,7 +3497,7 @@ CONFIG_HW_CONSOLE=y CONFIG_VT_HW_CONSOLE_BINDING=y CONFIG_UNIX98_PTYS=y # CONFIG_LEGACY_PTYS is not set -CONFIG_LEGACY_TIOCSTI=y +# CONFIG_LEGACY_TIOCSTI is not set # CONFIG_LDISC_AUTOLOAD is not set
# diff --git a/config/rootfiles/common/aarch64/linux b/config/rootfiles/common/aarch64/linux index 5d2d36a46..a32c3770e 100644 --- a/config/rootfiles/common/aarch64/linux +++ b/config/rootfiles/common/aarch64/linux @@ -9185,7 +9185,6 @@ etc/modprobe.d/ipv6.conf #lib/modules/KVER-ipfire/build/include/config/LEDS_TRIGGER_TTY #lib/modules/KVER-ipfire/build/include/config/LED_TRIGGER_PHY #lib/modules/KVER-ipfire/build/include/config/LEGACY_DIRECT_IO -#lib/modules/KVER-ipfire/build/include/config/LEGACY_TIOCSTI #lib/modules/KVER-ipfire/build/include/config/LIB80211 #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_CCMP #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_TKIP diff --git a/config/rootfiles/common/riscv64/linux b/config/rootfiles/common/riscv64/linux index c2e0191af..5e1ac921c 100644 --- a/config/rootfiles/common/riscv64/linux +++ b/config/rootfiles/common/riscv64/linux @@ -8345,7 +8345,6 @@ etc/modprobe.d/ipv6.conf #lib/modules/KVER-ipfire/build/include/config/LEDS_USER #lib/modules/KVER-ipfire/build/include/config/LED_TRIGGER_PHY #lib/modules/KVER-ipfire/build/include/config/LEGACY_DIRECT_IO -#lib/modules/KVER-ipfire/build/include/config/LEGACY_TIOCSTI #lib/modules/KVER-ipfire/build/include/config/LIB80211 #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_CCMP #lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_TKIP diff --git a/config/rootfiles/common/x86_64/linux b/config/rootfiles/common/x86_64/linux index a51f3487f..f3a8dea19 100644 --- a/config/rootfiles/common/x86_64/linux +++ b/config/rootfiles/common/x86_64/linux @@ -8996,7 +8996,6 @@ etc/modprobe.d/ipv6.conf #lib/modules/KVER-ipfire/build/include/config/LEDS_USER #lib/modules/KVER-ipfire/build/include/config/LED_TRIGGER_PHY #lib/modules/KVER-ipfire/build/include/config/LEGACY_DIRECT_IO -#lib/modules/KVER-ipfire/build/include/config/LEGACY_TIOCSTI #lib/modules/KVER-ipfire/build/include/config/LEGACY_VSYSCALL_NONE #lib/modules/KVER-ipfire/build/include/config/LIB80211
#lib/modules/KVER-ipfire/build/include/config/LIB80211_CRYPT_CCMP
2.35.3
-
Michael Tremer -
Peter Müller