CVE-2022-49851
RISC-V Linux Kernel Reserved Memory Setup Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: riscv: fix reserved memory setup Currently, RISC-V sets up reserved memory using the "early" copy of the device tree. As a result, when trying to get a reserved memory region using of_reserved_mem_lookup(), the pointer to reserved memory regions is using the early, pre-virtual-memory address which causes a kernel panic when trying to use the buffer's name: Unable to handle kernel paging request at virtual address 00000000401c31ac Oops [#1] Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 6.0.0-rc1-00001-g0d9d6953d834 #1 Hardware name: Microchip PolarFire-SoC Icicle Kit (DT) epc : string+0x4a/0xea ra : vsnprintf+0x1e4/0x336 epc : ffffffff80335ea0 ra : ffffffff80338936 sp : ffffffff81203be0 gp : ffffffff812e0a98 tp : ffffffff8120de40 t0 : 0000000000000000 t1 : ffffffff81203e28 t2 : 7265736572203a46 s0 : ffffffff81203c20 s1 : ffffffff81203e28 a0 : ffffffff81203d22 a1 : 0000000000000000 a2 : ffffffff81203d08 a3 : 0000000081203d21 a4 : ffffffffffffffff a5 : 00000000401c31ac a6 : ffff0a00ffffff04 a7 : ffffffffffffffff s2 : ffffffff81203d08 s3 : ffffffff81203d00 s4 : 0000000000000008 s5 : ffffffff000000ff s6 : 0000000000ffffff s7 : 00000000ffffff00 s8 : ffffffff80d9821a s9 : ffffffff81203d22 s10: 0000000000000002 s11: ffffffff80d9821c t3 : ffffffff812f3617 t4 : ffffffff812f3617 t5 : ffffffff812f3618 t6 : ffffffff81203d08 status: 0000000200000100 badaddr: 00000000401c31ac cause: 000000000000000d [<ffffffff80338936>] vsnprintf+0x1e4/0x336 [<ffffffff80055ae2>] vprintk_store+0xf6/0x344 [<ffffffff80055d86>] vprintk_emit+0x56/0x192 [<ffffffff80055ed8>] vprintk_default+0x16/0x1e [<ffffffff800563d2>] vprintk+0x72/0x80 [<ffffffff806813b2>] _printk+0x36/0x50 [<ffffffff8068af48>] print_reserved_mem+0x1c/0x24 [<ffffffff808057ec>] paging_init+0x528/0x5bc [<ffffffff808031ae>] setup_arch+0xd0/0x592 [<ffffffff8080070e>] start_kernel+0x82/0x73c early_init_fdt_scan_reserved_mem() takes no arguments as it operates on initial_boot_params, which is populated by early_init_dt_verify(). On RISC-V, early_init_dt_verify() is called twice. Once, directly, in setup_arch() if CONFIG_BUILTIN_DTB is not enabled and once indirectly, very early in the boot process, by parse_dtb() when it calls early_init_dt_scan_nodes(). This first call uses dtb_early_va to set initial_boot_params, which is not usable later in the boot process when early_init_fdt_scan_reserved_mem() is called. On arm64 for example, the corresponding call to early_init_dt_scan_nodes() uses fixmap addresses and doesn't suffer the same fate. Move early_init_fdt_scan_reserved_mem() further along the boot sequence, after the direct call to early_init_dt_verify() in setup_arch() so that the names use the correct virtual memory addresses. The above supposed that CONFIG_BUILTIN_DTB was not set, but should work equally in the case where it is - unflatted_and_copy_device_tree() also updates initial_boot_params.
INFO
Published Date :
May 1, 2025, 3:16 p.m.
Last Modified :
May 2, 2025, 1:53 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
Exploitability Score :
References to Advisories, Solutions, and Tools
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CVE-2022-49851.
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 01, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: riscv: fix reserved memory setup Currently, RISC-V sets up reserved memory using the "early" copy of the device tree. As a result, when trying to get a reserved memory region using of_reserved_mem_lookup(), the pointer to reserved memory regions is using the early, pre-virtual-memory address which causes a kernel panic when trying to use the buffer's name: Unable to handle kernel paging request at virtual address 00000000401c31ac Oops [#1] Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 6.0.0-rc1-00001-g0d9d6953d834 #1 Hardware name: Microchip PolarFire-SoC Icicle Kit (DT) epc : string+0x4a/0xea ra : vsnprintf+0x1e4/0x336 epc : ffffffff80335ea0 ra : ffffffff80338936 sp : ffffffff81203be0 gp : ffffffff812e0a98 tp : ffffffff8120de40 t0 : 0000000000000000 t1 : ffffffff81203e28 t2 : 7265736572203a46 s0 : ffffffff81203c20 s1 : ffffffff81203e28 a0 : ffffffff81203d22 a1 : 0000000000000000 a2 : ffffffff81203d08 a3 : 0000000081203d21 a4 : ffffffffffffffff a5 : 00000000401c31ac a6 : ffff0a00ffffff04 a7 : ffffffffffffffff s2 : ffffffff81203d08 s3 : ffffffff81203d00 s4 : 0000000000000008 s5 : ffffffff000000ff s6 : 0000000000ffffff s7 : 00000000ffffff00 s8 : ffffffff80d9821a s9 : ffffffff81203d22 s10: 0000000000000002 s11: ffffffff80d9821c t3 : ffffffff812f3617 t4 : ffffffff812f3617 t5 : ffffffff812f3618 t6 : ffffffff81203d08 status: 0000000200000100 badaddr: 00000000401c31ac cause: 000000000000000d [<ffffffff80338936>] vsnprintf+0x1e4/0x336 [<ffffffff80055ae2>] vprintk_store+0xf6/0x344 [<ffffffff80055d86>] vprintk_emit+0x56/0x192 [<ffffffff80055ed8>] vprintk_default+0x16/0x1e [<ffffffff800563d2>] vprintk+0x72/0x80 [<ffffffff806813b2>] _printk+0x36/0x50 [<ffffffff8068af48>] print_reserved_mem+0x1c/0x24 [<ffffffff808057ec>] paging_init+0x528/0x5bc [<ffffffff808031ae>] setup_arch+0xd0/0x592 [<ffffffff8080070e>] start_kernel+0x82/0x73c early_init_fdt_scan_reserved_mem() takes no arguments as it operates on initial_boot_params, which is populated by early_init_dt_verify(). On RISC-V, early_init_dt_verify() is called twice. Once, directly, in setup_arch() if CONFIG_BUILTIN_DTB is not enabled and once indirectly, very early in the boot process, by parse_dtb() when it calls early_init_dt_scan_nodes(). This first call uses dtb_early_va to set initial_boot_params, which is not usable later in the boot process when early_init_fdt_scan_reserved_mem() is called. On arm64 for example, the corresponding call to early_init_dt_scan_nodes() uses fixmap addresses and doesn't suffer the same fate. Move early_init_fdt_scan_reserved_mem() further along the boot sequence, after the direct call to early_init_dt_verify() in setup_arch() so that the names use the correct virtual memory addresses. The above supposed that CONFIG_BUILTIN_DTB was not set, but should work equally in the case where it is - unflatted_and_copy_device_tree() also updates initial_boot_params. Added Reference https://git.kernel.org/stable/c/50e63dd8ed92045eb70a72d7ec725488320fb68b Added Reference https://git.kernel.org/stable/c/518e49f0590de66555503aabe199ba8d3f2e24ac Added Reference https://git.kernel.org/stable/c/93598deb101540c4f9e7de15099ea8255b965fc2 Added Reference https://git.kernel.org/stable/c/94ab8f88feb75e3b1486102c0c9c550f37d9d137
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2022-49851 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2022-49851
weaknesses.