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https://github.com/fkie-cad/nvd-json-data-feeds.git
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25 lines
4.6 KiB
JSON
25 lines
4.6 KiB
JSON
{
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"id": "CVE-2024-41003",
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"published": "2024-07-12T13:15:21.180",
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"lastModified": "2024-07-12T13:15:21.180",
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"vulnStatus": "Received",
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"cveTags": [],
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix reg_set_min_max corruption of fake_reg\n\nJuan reported that after doing some changes to buzzer [0] and implementing\na new fuzzing strategy guided by coverage, they noticed the following in\none of the probes:\n\n [...]\n 13: (79) r6 = *(u64 *)(r0 +0) ; R0=map_value(ks=4,vs=8) R6_w=scalar()\n 14: (b7) r0 = 0 ; R0_w=0\n 15: (b4) w0 = -1 ; R0_w=0xffffffff\n 16: (74) w0 >>= 1 ; R0_w=0x7fffffff\n 17: (5c) w6 &= w0 ; R0_w=0x7fffffff R6_w=scalar(smin=smin32=0,smax=umax=umax32=0x7fffffff,var_off=(0x0; 0x7fffffff))\n 18: (44) w6 |= 2 ; R6_w=scalar(smin=umin=smin32=umin32=2,smax=umax=umax32=0x7fffffff,var_off=(0x2; 0x7ffffffd))\n 19: (56) if w6 != 0x7ffffffd goto pc+1\n REG INVARIANTS VIOLATION (true_reg2): range bounds violation u64=[0x7fffffff, 0x7ffffffd] s64=[0x7fffffff, 0x7ffffffd] u32=[0x7fffffff, 0x7ffffffd] s32=[0x7fffffff, 0x7ffffffd] var_off=(0x7fffffff, 0x0)\n REG INVARIANTS VIOLATION (false_reg1): range bounds violation u64=[0x7fffffff, 0x7ffffffd] s64=[0x7fffffff, 0x7ffffffd] u32=[0x7fffffff, 0x7ffffffd] s32=[0x7fffffff, 0x7ffffffd] var_off=(0x7fffffff, 0x0)\n REG INVARIANTS VIOLATION (false_reg2): const tnum out of sync with range bounds u64=[0x0, 0xffffffffffffffff] s64=[0x8000000000000000, 0x7fffffffffffffff] u32=[0x0, 0xffffffff] s32=[0x80000000, 0x7fffffff] var_off=(0x7fffffff, 0x0)\n 19: R6_w=0x7fffffff\n 20: (95) exit\n\n from 19 to 21: R0=0x7fffffff R6=scalar(smin=umin=smin32=umin32=2,smax=umax=smax32=umax32=0x7ffffffe,var_off=(0x2; 0x7ffffffd)) R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm\n 21: R0=0x7fffffff R6=scalar(smin=umin=smin32=umin32=2,smax=umax=smax32=umax32=0x7ffffffe,var_off=(0x2; 0x7ffffffd)) R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm\n 21: (14) w6 -= 2147483632 ; R6_w=scalar(smin=umin=umin32=2,smax=umax=0xffffffff,smin32=0x80000012,smax32=14,var_off=(0x2; 0xfffffffd))\n 22: (76) if w6 s>= 0xe goto pc+1 ; R6_w=scalar(smin=umin=umin32=2,smax=umax=0xffffffff,smin32=0x80000012,smax32=13,var_off=(0x2; 0xfffffffd))\n 23: (95) exit\n\n from 22 to 24: R0=0x7fffffff R6_w=14 R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm\n 24: R0=0x7fffffff R6_w=14 R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm\n 24: (14) w6 -= 14 ; R6_w=0\n [...]\n\nWhat can be seen here is a register invariant violation on line 19. After\nthe binary-or in line 18, the verifier knows that bit 2 is set but knows\nnothing about the rest of the content which was loaded from a map value,\nmeaning, range is [2,0x7fffffff] with var_off=(0x2; 0x7ffffffd). When in\nline 19 the verifier analyzes the branch, it splits the register states\nin reg_set_min_max() into the registers of the true branch (true_reg1,\ntrue_reg2) and the registers of the false branch (false_reg1, false_reg2).\n\nSince the test is w6 != 0x7ffffffd, the src_reg is a known constant.\nInternally, the verifier creates a \"fake\" register initialized as scalar\nto the value of 0x7ffffffd, and then passes it onto reg_set_min_max(). Now,\nfor line 19, it is mathematically impossible to take the false branch of\nthis program, yet the verifier analyzes it. It is impossible because the\nsecond bit of r6 will be set due to the prior or operation and the\nconstant in the condition has that bit unset (hex(fd) == binary(1111 1101).\n\nWhen the verifier first analyzes the false / fall-through branch, it will\ncompute an intersection between the var_off of r6 and of the constant. This\nis because the verifier creates a \"fake\" register initialized to the value\nof the constant. The intersection result later refines both registers in\nregs_refine_cond_op():\n\n [...]\n t = tnum_intersect(tnum_subreg(reg1->var_off), tnum_subreg(reg2->var_off));\n reg1->var_o\n---truncated---"
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}
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],
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"metrics": {},
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/41e8ab428a9964df378fa45760a660208712145b",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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},
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{
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"url": "https://git.kernel.org/stable/c/92424801261d1564a0bb759da3cf3ccd69fdf5a2",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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}
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]
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} |