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.przyw...@arm.com>
---
 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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