diff options
Diffstat (limited to 'pcr/qemu-user-static-git/0004-linux-user-init_guest_space-Correctly-handle-guest_s.patch')
-rw-r--r-- | pcr/qemu-user-static-git/0004-linux-user-init_guest_space-Correctly-handle-guest_s.patch | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/pcr/qemu-user-static-git/0004-linux-user-init_guest_space-Correctly-handle-guest_s.patch b/pcr/qemu-user-static-git/0004-linux-user-init_guest_space-Correctly-handle-guest_s.patch new file mode 100644 index 000000000..7f9cfc7a8 --- /dev/null +++ b/pcr/qemu-user-static-git/0004-linux-user-init_guest_space-Correctly-handle-guest_s.patch @@ -0,0 +1,47 @@ +From bc26025ccc64a2a63fc58776c93e2e4392445abe Mon Sep 17 00:00:00 2001 +From: Luke Shumaker <lukeshu@parabola.nu> +Date: Wed, 27 Dec 2017 19:44:00 -0500 +Subject: [PATCH 04/10] linux-user: init_guest_space: Correctly handle + guest_start in commpage initialization + +init_guest_commpage needs to check if the mapped space, which ends at +real_start+real_size overlaps with where it needs to put the commpage, +which is (assuming sane qemu_host_page_size) guest_base + 0xffff000, where +guest_base is real_start - guest_start. + + [guest_base][ 0xffff0000 ][commpage] + [guest_base][guest_start][real_size] [commpage] + [ real_start ][real_size] [commpage] + ^ + fail if this gap < 0 + +Since init_guest_commpage wants to do everything relative to guest_base +(rather than real_start), it obviously needs to be comparing 0xffff0000 +against guest_start+real_size, not just real_size. + +This bug has been present since 806d102141b99d4f1e55a97d68b7ea8c8ba3129f in +2012, but guest_start is usually 0, and prior to v2.11 real_size was +usually much smaller than 0xffff0000, so it was uncommon for it to have +made a difference. + +Signed-off-by: Luke Shumaker <lukeshu@parabola.nu> +--- + linux-user/elfload.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/linux-user/elfload.c b/linux-user/elfload.c +index 1a6b660b25..f41cecc3cb 100644 +--- a/linux-user/elfload.c ++++ b/linux-user/elfload.c +@@ -1882,7 +1882,7 @@ unsigned long init_guest_space(unsigned long host_start, + #if defined(TARGET_ARM) && !defined(TARGET_AARCH64) + /* On 32-bit ARM, we need to also be able to map the commpage. */ + int valid = init_guest_commpage(real_start - guest_start, +- real_size); ++ real_size + guest_start); + if (valid == 1) { + break; + } else if (valid == -1) { +-- +2.15.1 + |