[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.15] xen/gnttab: fix gnttab_acquire_resource()
commit 3ac64b3751837a117ee3dfb3e2cc27057a83d0f7 Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Tue Oct 11 15:16:53 2022 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Oct 11 15:16:53 2022 +0200 xen/gnttab: fix gnttab_acquire_resource() Commit 9dc46386d89d ("gnttab: work around "may be used uninitialized" warning") was wrong, as vaddrs can legitimately be NULL in case XENMEM_resource_grant_table_id_status was specified for a grant table v1. This would result in crashes in debug builds due to ASSERT_UNREACHABLE() triggering. Check vaddrs only to be NULL in the rc == 0 case. Expand the tests in tools/tests/resource to tickle this path, and verify that using XENMEM_resource_grant_table_id_status on a v1 grant table fails. Fixes: 9dc46386d89d ("gnttab: work around "may be used uninitialized" warning") Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> # xen Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> master commit: 52daa6a8483e4fbd6757c9d1b791e23931791608 master date: 2022-09-09 16:28:38 +0100 --- tools/tests/resource/test-resource.c | 15 +++++++++++++++ xen/common/grant_table.c | 2 +- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/tools/tests/resource/test-resource.c b/tools/tests/resource/test-resource.c index 1caaa60e62..bf485baff2 100644 --- a/tools/tests/resource/test-resource.c +++ b/tools/tests/resource/test-resource.c @@ -63,6 +63,21 @@ static void test_gnttab(uint32_t domid, unsigned int nr_frames) rc = xenforeignmemory_unmap_resource(fh, res); if ( rc ) return fail(" Fail: Unmap %d - %s\n", errno, strerror(errno)); + + /* + * Verify that an attempt to map the status frames fails, as the domain is + * in gnttab v1 mode. + */ + res = xenforeignmemory_map_resource( + fh, domid, XENMEM_resource_grant_table, + XENMEM_resource_grant_table_id_status, 0, 1, + (void **)&gnttab, PROT_READ | PROT_WRITE, 0); + + if ( res ) + { + fail(" Fail: Managed to map gnttab v2 status frames in v1 mode\n"); + xenforeignmemory_unmap_resource(fh, res); + } } static void test_domain_configurations(void) diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c index 0523beb9b7..01e426c67f 100644 --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -4138,7 +4138,7 @@ int gnttab_acquire_resource( * on non-error paths, and hence it needs setting to NULL at the top of the * function. Leave some runtime safety. */ - if ( !vaddrs ) + if ( !rc && !vaddrs ) { ASSERT_UNREACHABLE(); rc = -ENODATA; -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.15
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