Replace the unsafe read-loops in the x86 kernel image loading
functions with our safe read_file() and read_in_full() wrappers.
This should fix random fails in kernel image loading, especially
from pipes and sockets.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
x86/kvm.c | 40 +++++++++++++++++++---------------------
1 file changed, 19 insertions(+), 21 deletions(-)
diff --git a/x86/kvm.c b/x86/kvm.c
index 9817953..8cf4ec6 100644
--- a/x86/kvm.c
+++ b/x86/kvm.c
@@ -9,6 +9,7 @@
#include <asm/bootparam.h>
#include <linux/kvm.h>
+#include <linux/kernel.h>
#include <sys/types.h>
#include <sys/ioctl.h>
@@ -209,15 +210,14 @@ static inline void *guest_real_to_host(struct kvm *kvm, u16 selector, u16 offset
static bool load_flat_binary(struct kvm *kvm, int fd_kernel, void *buf, int len)
{
void *p;
- int nr;
p = guest_real_to_host(kvm, BOOT_LOADER_SELECTOR, BOOT_LOADER_IP);
memcpy(p, buf, len);
p += len;
- while ((nr = read(fd_kernel, p, 65536)) > 0)
- p += nr;
+ if (read_file(fd_kernel, p, kvm->cfg.ram_size) < 0)
+ die_perror("read");
kvm->arch.boot_selector = BOOT_LOADER_SELECTOR;
kvm->arch.boot_ip = BOOT_LOADER_IP;
@@ -232,11 +232,9 @@ static bool load_bzimage(struct kvm *kvm, int fd_kernel, int fd_initrd,
const char *kernel_cmdline, struct boot_params *boot)
{
struct boot_params *kern_boot;
- unsigned long setup_sects;
size_t cmdline_size;
- ssize_t setup_size;
+ ssize_t file_size;
void *p;
- int nr;
u16 vidmode;
/*
@@ -250,25 +248,26 @@ static bool load_bzimage(struct kvm *kvm, int fd_kernel, int fd_initrd,
if (boot->hdr.version < BOOT_PROTOCOL_REQUIRED)
die("Too old kernel");
+ /* read real-mode setup.bin to boot loader address */
+ p = guest_real_to_host(kvm, BOOT_LOADER_SELECTOR, BOOT_LOADER_IP);
if (!boot->hdr.setup_sects)
boot->hdr.setup_sects = BZ_DEFAULT_SETUP_SECTS;
- setup_sects = boot->hdr.setup_sects + 1;
-
- setup_size = setup_sects << 9;
- p = guest_real_to_host(kvm, BOOT_LOADER_SELECTOR, BOOT_LOADER_IP);
+ file_size = (boot->hdr.setup_sects + 1) << 9;
- /* copy setup.bin to mem */
+ /* copy in the part already read earlier from the file */
memcpy(p, boot, sizeof(struct boot_params));
p += sizeof(struct boot_params);
- setup_size -= sizeof(struct boot_params);
- if (read(fd_kernel, p, setup_size) != setup_size)
- die_perror("read");
+ file_size -= sizeof(struct boot_params);
- /* copy vmlinux.bin to BZ_KERNEL_START*/
- p = guest_flat_to_host(kvm, BZ_KERNEL_START);
+ if (read_in_full(fd_kernel, p, file_size) != file_size)
+ die_perror("kernel setup read");
- while ((nr = read(fd_kernel, p, 65536)) > 0)
- p += nr;
+ /* read actual kernel image (vmlinux.bin) to BZ_KERNEL_START */
+ p = guest_flat_to_host(kvm, BZ_KERNEL_START);
+ file_size = read_file(fd_kernel, p,
+ kvm->cfg.ram_size - BZ_KERNEL_START);
+ if (file_size < 0)
+ die_perror("kernel read");
p = guest_flat_to_host(kvm, BOOT_CMDLINE_OFFSET);
if (kernel_cmdline) {
@@ -319,8 +318,7 @@ static bool load_bzimage(struct kvm *kvm, int fd_kernel, int fd_initrd,
}
p = guest_flat_to_host(kvm, addr);
- nr = read(fd_initrd, p, initrd_stat.st_size);
- if (nr != initrd_stat.st_size)
+ if (read_in_full(fd_initrd, p, initrd_stat.st_size) < 0)
die("Failed to read initrd");
kern_boot->hdr.ramdisk_image = addr;
@@ -343,7 +341,7 @@ bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
{
struct boot_params boot;
- if (read(fd_kernel, &boot, sizeof(boot)) != sizeof(boot))
+ if (read_in_full(fd_kernel, &boot, sizeof(boot)) != sizeof(boot))
return false;
if (load_bzimage(kvm, fd_kernel, fd_initrd, kernel_cmdline, &boot))
--
2.3.5
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