Date: Tue, 4 Oct 2016 16:33:03 +0000 (UTC) From: Allan Jude <allanjude@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r306677 - head/sys/boot/geli Message-ID: <201610041633.u94GX3HL051604@repo.freebsd.org>
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Author: allanjude Date: Tue Oct 4 16:33:03 2016 New Revision: 306677 URL: https://svnweb.freebsd.org/changeset/base/306677 Log: GELIBoot may attempt to read past the end of the disk Usually there is some slack after the last partition due to 4k alignment In the 10.3 EC2 images, there was not. EC2 seems to hang if you try to read past the end of the disk in the loader, resulting in an unbootable instance after upgrading to 11.0 PR: 213196 Reported by: Peter Ankerstal <peter@pean.org> Tested by: cperciva Reviewed by: tsoome MFC after: 3 days Sponsored by: ScaleEngine Inc. Differential Revision: https://reviews.freebsd.org/D8144 Modified: head/sys/boot/geli/geliboot.c Modified: head/sys/boot/geli/geliboot.c ============================================================================== --- head/sys/boot/geli/geliboot.c Tue Oct 4 16:29:26 2016 (r306676) +++ head/sys/boot/geli/geliboot.c Tue Oct 4 16:33:03 2016 (r306677) @@ -77,17 +77,25 @@ geli_taste(int read_func(void *vdev, voi int error; off_t alignsector; - alignsector = (lastsector * DEV_BSIZE) & - ~(off_t)(DEV_GELIBOOT_BSIZE - 1); + alignsector = rounddown2(lastsector * DEV_BSIZE, DEV_GELIBOOT_BSIZE); + if (alignsector + DEV_GELIBOOT_BSIZE > ((lastsector + 1) * DEV_BSIZE)) { + /* Don't read past the end of the disk */ + alignsector = (lastsector * DEV_BSIZE) + DEV_BSIZE + - DEV_GELIBOOT_BSIZE; + } error = read_func(NULL, dskp, alignsector, &buf, DEV_GELIBOOT_BSIZE); if (error != 0) { return (error); } - /* Extract the last DEV_BSIZE bytes from the block. */ - error = eli_metadata_decode(buf + (DEV_GELIBOOT_BSIZE - DEV_BSIZE), - &md); + /* Extract the last 4k sector of the disk. */ + error = eli_metadata_decode(buf, &md); if (error != 0) { - return (error); + /* Try the last 512 byte sector instead. */ + error = eli_metadata_decode(buf + + (DEV_GELIBOOT_BSIZE - DEV_BSIZE), &md); + if (error != 0) { + return (error); + } } if (!(md.md_flags & G_ELI_FLAG_GELIBOOT)) {
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