Date: Mon, 18 Jan 2021 17:24:50 -0800 From: Ravi Pokala <rpokala@freebsd.org> To: Toomas Soome <tsoome@FreeBSD.org>, <src-committers@FreeBSD.org>, <dev-commits-src-all@FreeBSD.org>, <dev-commits-src-main@FreeBSD.org> Subject: Re: ad1ebbe5cea8 - main - loader: create local copy of mode list provided by vbeinfoblock Message-ID: <7FCB573F-0BC6-429E-919C-6A87513DBD63@panasas.com> In-Reply-To: <202101160823.10G8NjEi016925@gitrepo.freebsd.org> References: <202101160823.10G8NjEi016925@gitrepo.freebsd.org>
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Hi Toomas, =EF=BB=BF-----Original Message----- From: <owner-src-committers@freebsd.org> on behalf of Toomas Soome <tsoome@= FreeBSD.org> Date: 2021-01-16, Saturday at 00:23 To: <src-committers@FreeBSD.org>, <dev-commits-src-all@FreeBSD.org>, <dev-c= ommits-src-main@FreeBSD.org> Subject: git: ad1ebbe5cea8 - main - loader: create local copy of mode list = provided by vbeinfoblock The branch main has been updated by tsoome: URL: https://cgit.FreeBSD.org/src/commit/?id=3Dad1ebbe5cea8ffac0037966990= ddf0f80faa55d5 commit ad1ebbe5cea8ffac0037966990ddf0f80faa55d5 Author: Toomas Soome <tsoome@FreeBSD.org> AuthorDate: 2021-01-16 10:18:32 +0000 Commit: Toomas Soome <tsoome@FreeBSD.org> CommitDate: 2021-01-16 10:23:22 +0000 loader: create local copy of mode list provided by vbeinfoblock Apparently some systems do corrupt mode list memory area, so we nee= d to use local copy instead. ... + vbe_mode_list_size =3D (uintptr_t)p - (uintptr_t)ml; + vbe_mode_list =3D malloc(vbe_mode_list_size); + if (vbe_mode_list =3D=3D NULL) { + free(vbe); + vbe =3D NULL; + free(vbe_mode); + vbe_mode =3D NULL; + } + bcopy(ml, vbe_mode_list, vbe_mode_list_size); + + /* reset VideoModePtr, so we will not have chance to use bad data. */ + vbe->VideoModePtr =3D 0; If allocation of vbe_mode_list failed, you're freeing things that were allo= cated before it, but then you're continuing on. The very next thing you do i= s the bcopy(), which dereferences vbe_mode_list, which is NULL because of th= e allocation failure. That doesn't seem right. Thanks, Ravi (rpokala@)
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