ghsa-28pg-93m7-9jmx
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
uprobe: avoid out-of-bounds memory access of fetching args
Uprobe needs to fetch args into a percpu buffer, and then copy to ring buffer to avoid non-atomic context problem.
Sometimes user-space strings, arrays can be very large, but the size of percpu buffer is only page size. And store_trace_args() won't check whether these data exceeds a single page or not, caused out-of-bounds memory access.
It could be reproduced by following steps: 1. build kernel with CONFIG_KASAN enabled 2. save follow program as test.c
```
#include
// If string length large than MAX_STRING_SIZE, the fetch_store_strlen() // will return 0, cause __get_data_size() return shorter size, and // store_trace_args() will not trigger out-of-bounds access. // So make string length less than 4096. #define STRLEN 4093
void generate_string(char *str, int n) { int i; for (i = 0; i < n; ++i) { char c = i % 26 + 'a'; str[i] = c; } str[n-1] = '\0'; }
void print_string(char *str) { printf("%s\n", str); }
int main() { char tmp[STRLEN];
generate_string(tmp, STRLEN);
print_string(tmp);
return 0;
}
``
3. compile programgcc -o test test.c`
-
get the offset of
print_string()objdump -t test | grep -w print_string 0000000000401199 g F .text 000000000000001b print_string -
configure uprobe with offset 0x1199 ``` off=0x1199
cd /sys/kernel/debug/tracing/ echo "p /root/test:${off} arg1=+0(%di):ustring arg2=\$comm arg3=+0(%di):ustring"
uprobe_events echo 1 > events/uprobes/enable echo 1 > tracing_on ```
6. run test, and kasan will report error.
BUG: KASAN: use-after-free in strncpy_from_user+0x1d6/0x1f0
Write of size 8 at addr ffff88812311c004 by task test/499CPU: 0 UID: 0 PID: 499 Comm: test Not tainted 6.12.0-rc3+ #18
Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014
Call Trace:
This commit enforces the buffer's maxlen less than a page-size to avoid store_trace_args() out-of-memory access.
{
"affected": [],
"aliases": [
"CVE-2024-50067"
],
"database_specific": {
"cwe_ids": [
"CWE-416",
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-10-28T01:15:02Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nuprobe: avoid out-of-bounds memory access of fetching args\n\nUprobe needs to fetch args into a percpu buffer, and then copy to ring\nbuffer to avoid non-atomic context problem.\n\nSometimes user-space strings, arrays can be very large, but the size of\npercpu buffer is only page size. And store_trace_args() won\u0027t check\nwhether these data exceeds a single page or not, caused out-of-bounds\nmemory access.\n\nIt could be reproduced by following steps:\n1. build kernel with CONFIG_KASAN enabled\n2. save follow program as test.c\n\n```\n\\#include \u003cstdio.h\u003e\n\\#include \u003cstdlib.h\u003e\n\\#include \u003cstring.h\u003e\n\n// If string length large than MAX_STRING_SIZE, the fetch_store_strlen()\n// will return 0, cause __get_data_size() return shorter size, and\n// store_trace_args() will not trigger out-of-bounds access.\n// So make string length less than 4096.\n\\#define STRLEN 4093\n\nvoid generate_string(char *str, int n)\n{\n int i;\n for (i = 0; i \u003c n; ++i)\n {\n char c = i % 26 + \u0027a\u0027;\n str[i] = c;\n }\n str[n-1] = \u0027\\0\u0027;\n}\n\nvoid print_string(char *str)\n{\n printf(\"%s\\n\", str);\n}\n\nint main()\n{\n char tmp[STRLEN];\n\n generate_string(tmp, STRLEN);\n print_string(tmp);\n\n return 0;\n}\n```\n3. compile program\n`gcc -o test test.c`\n\n4. get the offset of `print_string()`\n```\nobjdump -t test | grep -w print_string\n0000000000401199 g F .text 000000000000001b print_string\n```\n\n5. configure uprobe with offset 0x1199\n```\noff=0x1199\n\ncd /sys/kernel/debug/tracing/\necho \"p /root/test:${off} arg1=+0(%di):ustring arg2=\\$comm arg3=+0(%di):ustring\"\n \u003e uprobe_events\necho 1 \u003e events/uprobes/enable\necho 1 \u003e tracing_on\n```\n\n6. run `test`, and kasan will report error.\n==================================================================\nBUG: KASAN: use-after-free in strncpy_from_user+0x1d6/0x1f0\nWrite of size 8 at addr ffff88812311c004 by task test/499CPU: 0 UID: 0 PID: 499 Comm: test Not tainted 6.12.0-rc3+ #18\nHardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x55/0x70\n print_address_description.constprop.0+0x27/0x310\n kasan_report+0x10f/0x120\n ? strncpy_from_user+0x1d6/0x1f0\n strncpy_from_user+0x1d6/0x1f0\n ? rmqueue.constprop.0+0x70d/0x2ad0\n process_fetch_insn+0xb26/0x1470\n ? __pfx_process_fetch_insn+0x10/0x10\n ? _raw_spin_lock+0x85/0xe0\n ? __pfx__raw_spin_lock+0x10/0x10\n ? __pte_offset_map+0x1f/0x2d0\n ? unwind_next_frame+0xc5f/0x1f80\n ? arch_stack_walk+0x68/0xf0\n ? is_bpf_text_address+0x23/0x30\n ? kernel_text_address.part.0+0xbb/0xd0\n ? __kernel_text_address+0x66/0xb0\n ? unwind_get_return_address+0x5e/0xa0\n ? __pfx_stack_trace_consume_entry+0x10/0x10\n ? arch_stack_walk+0xa2/0xf0\n ? _raw_spin_lock_irqsave+0x8b/0xf0\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? depot_alloc_stack+0x4c/0x1f0\n ? _raw_spin_unlock_irqrestore+0xe/0x30\n ? stack_depot_save_flags+0x35d/0x4f0\n ? kasan_save_stack+0x34/0x50\n ? kasan_save_stack+0x24/0x50\n ? mutex_lock+0x91/0xe0\n ? __pfx_mutex_lock+0x10/0x10\n prepare_uprobe_buffer.part.0+0x2cd/0x500\n uprobe_dispatcher+0x2c3/0x6a0\n ? __pfx_uprobe_dispatcher+0x10/0x10\n ? __kasan_slab_alloc+0x4d/0x90\n handler_chain+0xdd/0x3e0\n handle_swbp+0x26e/0x3d0\n ? __pfx_handle_swbp+0x10/0x10\n ? uprobe_pre_sstep_notifier+0x151/0x1b0\n irqentry_exit_to_user_mode+0xe2/0x1b0\n asm_exc_int3+0x39/0x40\nRIP: 0033:0x401199\nCode: 01 c2 0f b6 45 fb 88 02 83 45 fc 01 8b 45 fc 3b 45 e4 7c b7 8b 45 e4 48 98 48 8d 50 ff 48 8b 45 e8 48 01 d0 ce\nRSP: 002b:00007ffdf00576a8 EFLAGS: 00000206\nRAX: 00007ffdf00576b0 RBX: 0000000000000000 RCX: 0000000000000ff2\nRDX: 0000000000000ffc RSI: 0000000000000ffd RDI: 00007ffdf00576b0\nRBP: 00007ffdf00586b0 R08: 00007feb2f9c0d20 R09: 00007feb2f9c0d20\nR10: 0000000000000001 R11: 0000000000000202 R12: 0000000000401040\nR13: 00007ffdf0058780 R14: 0000000000000000 R15: 0000000000000000\n \u003c/TASK\u003e\n\nThis commit enforces the buffer\u0027s maxlen less than a page-size to avoid\nstore_trace_args() out-of-memory access.",
"id": "GHSA-28pg-93m7-9jmx",
"modified": "2024-11-17T15:30:45Z",
"published": "2024-10-28T03:30:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-50067"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0dc3ad9ad2188da7f090b3dbe4d2fcd9ae8ae64f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/373b9338c9722a368925d83bc622c596896b328e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/537ad4a431f6dddbf15d40d19f24bb9ee12b55cb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9e5f93788c9dd4309e75a56860a1ac44a8e117b9"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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