Respect the size of the real-mode boot header when zeroing and copying
in the command line, to avoid stomping on the BIOS EBCA or risk BIOS
SMM code stomping on the command line.
Signed-off-by: Ed Swierk <eswi...@skyportsystems.com>
---
tboot/common/linux.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/tboot/common/linux.c b/tboot/common/linux.c
index e9bb12e..3572d5f 100644
--- a/tboot/common/linux.c
+++ b/tboot/common/linux.c
@@ -303,14 +303,17 @@ bool expand_linux_image(const void *linux_image, size_t
linux_size,
/* copy cmdline */
const char *kernel_cmdline = get_cmdline(g_ldr_ctx);
+ const size_t kernel_cmdline_size = REAL_END_OFFSET - KERNEL_CMDLINE_OFFSET;
+ size_t kernel_cmdline_strlen = strlen(kernel_cmdline);
+ if (kernel_cmdline_strlen > kernel_cmdline_size)
+ kernel_cmdline_strlen = kernel_cmdline_size - 1;
+ memset((void *)hdr->cmd_line_ptr, 0, kernel_cmdline_size);
+ memcpy((void *)hdr->cmd_line_ptr, kernel_cmdline, kernel_cmdline_strlen);
- printk(TBOOT_INFO"Linux cmdline placed in header: ");
- printk_long(kernel_cmdline);
- printk(TBOOT_INFO"\n");
-
- memset((void *)hdr->cmd_line_ptr,0,TBOOT_KERNEL_CMDLINE_SIZE);
-
- memcpy((void *)hdr->cmd_line_ptr, kernel_cmdline, strlen(kernel_cmdline));
+ printk(TBOOT_INFO"Linux cmdline from 0x%lx to 0x%lx:\n",
+ (unsigned long)hdr->cmd_line_ptr,
+ (unsigned long)(hdr->cmd_line_ptr + kernel_cmdline_size));
+ printk_long((void *)hdr->cmd_line_ptr);
/* need to put boot_params in real mode area so it gets mapped */
boot_params = (boot_params_t *)(real_mode_base + real_mode_size);
--
1.9.1
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot
_______________________________________________
tboot-devel mailing list
tboot-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/tboot-devel
