In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
forcedeth: fix off-by-one when saving\/restoring non-PCI config space<\/p>\n
nv_suspend() and nv_resume() walk the non-PCI configuration space with<\/p>\n
\tfor (i = 0; i register_size\/sizeof(u32); i++)<\/p>\n
which runs one iteration too many. saved_config_space is declared as<\/p>\n
\tu32 saved_config_space[NV_PCI_REGSZ_MAX\/4];<\/p>\n
and NV_PCI_REGSZ_VER3 is equal to NV_PCI_REGSZ_MAX (0x604), so on a VER3
\ndevice register_size\/sizeof(u32) is exactly the array length and the last
\niteration addresses one element past the end.<\/p>\n
The element it lands on is np->name_rx[0..3]: saved_config_space[] is
\nfollowed immediately by char name_rx[IFNAMSIZ + 3], and char needs no
\npadding. Nothing observable is corrupted by that, because nv_request_irq()
\nrewrites name_rx with sprintf() before it is ever passed to request_irq().
\nThe bug is the out-of-bounds access itself, which UBSAN reports and which
\nCONFIG_UBSAN_TRAP=y turns into a trap that aborts the running kernel code,
\nplus an MMIO read and, on resume, an MMIO writel() to base + 0x604, one
\ndword past the range the driver mapped:<\/p>\n
\tnp->base = ioremap(addr, np->register_size);<\/p>\n
VER1 and VER2 devices stay inside the array, but they too get the stray
\nread and the stray write one dword past their own window.<\/p>\n
Caught by UBSAN on an Apple Macmini3,1 (MCP79) during a deep S3 cycle.
\nThe splat below is trimmed: the build path in the file name, the CPU
\nand taint lines, the Workqueue line, the “?” hint frames, and the
\nframes below device_suspend are all cut. The kernel was tainted, with
\nan out-of-tree nouveau and CPU_OUT_OF_SPEC; forcedeth itself was the
\nstock module.<\/p>\n
UBSAN: array-index-out-of-bounds in drivers\/net\/ethernet\/nvidia\/forcedeth.c:6225:25
\n index 385 is out of range for type ‘u32 [385]’
\n Call Trace:
\n dump_stack_lvl+0x5d\/0x80
\n ubsan_epilogue+0x5\/0x2b
\n __ubsan_handle_out_of_bounds.cold+0x54\/0x59
\n __this_module+0xe398c\/0xe9010 [forcedeth]
\n pci_pm_suspend+0x80\/0x170
\n dpm_run_callback+0x51\/0x160
\n device_suspend+0x1a2\/0x4a0
\n …<\/p>\n
Both loops are hit. UBSAN reports each source location only once per module
\nload (__ubsan_handle_out_of_bounds() calls suppress_report(), which does
\ntest_and_set_bit(REPORTED_BIT, …) on the struct source_location), so the
\ntwo splats land in the first S3 cycle after the module is loaded and later
\ncycles are silent even though the access still runs off the end every time.
\nIn that first cycle line 6225 is reported from pci_pm_suspend and line 6240
\nfrom pci_pm_resume.<\/p>\n
The same off-by-one was fixed in nv_get_regs() by commit ba9aa134287f
\n(“forcedeth: fix buffer overflow”) in 2012; these two loops were missed.
\nThe suspend and resume side was reported on LKML in September 2013 by Marc
\nWeber, with the same analysis and the same one-character fix, but the patch
\nwas attached rather than sent inline and the thread ended there.<\/p>\n
Use < instead of <=, which saves and restores exactly register_size bytes.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
forcedeth: fix off-by-one when saving\/restoring non-PCI config space<\/p>\n
nv_suspend() and nv_resume() walk the non-PCI configuration s<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21518","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21518","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21518"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21518"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21518"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}