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authorZachary Amsden <zach@vmware.com>2006-01-06 00:11:55 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-06 08:33:35 -0800
commit5fe9fe3c6f9a1ae7aa224bb7a66eb9aad9e4abef (patch)
treeec120ce6e72700fe49720127bc76228c51bd406b
parent3fae1c37eea98097de34ba665796fea93b29f4aa (diff)
downloadop-kernel-dev-5fe9fe3c6f9a1ae7aa224bb7a66eb9aad9e4abef.zip
op-kernel-dev-5fe9fe3c6f9a1ae7aa224bb7a66eb9aad9e4abef.tar.gz
[PATCH] x86: Pnp byte granularity
The one remaining caller of set_limit, the PnP BIOS code, calls into the PnP BIOS, passing kernel parameters in and out. These parameteres may be passed from arbitrary kernel virtual memory, so they deserve strict protection to stop a bad BIOS from smashing beyond the object size. Unfortunately, the use of set_limit was badly botching this by setting the limit in terms of pages, when it really should have byte granularity. When doing this, I discovered my BIOS had the buggy code during the "get system device node" call: mov ax, es:[bx] Which is harmless, but has a trivial workaround. Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: "Seth, Rohit" <rohit.seth@intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/head.S12
-rw-r--r--drivers/pnp/pnpbios/bioscalls.c5
-rw-r--r--include/asm-i386/system.h2
3 files changed, 11 insertions, 8 deletions
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index 37b599f..58d2746 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -504,12 +504,12 @@ ENTRY(cpu_gdt_table)
.quad 0x0000000000000000 /* 0x80 TSS descriptor */
.quad 0x0000000000000000 /* 0x88 LDT descriptor */
- /* Segments used for calling PnP BIOS */
- .quad 0x00c09a0000000000 /* 0x90 32-bit code */
- .quad 0x00809a0000000000 /* 0x98 16-bit code */
- .quad 0x0080920000000000 /* 0xa0 16-bit data */
- .quad 0x0080920000000000 /* 0xa8 16-bit data */
- .quad 0x0080920000000000 /* 0xb0 16-bit data */
+ /* Segments used for calling PnP BIOS have byte granularity */
+ .quad 0x00409a0000000000 /* 0x90 32-bit code */
+ .quad 0x00009a0000000000 /* 0x98 16-bit code */
+ .quad 0x0000920000000000 /* 0xa0 16-bit data */
+ .quad 0x0000920000000000 /* 0xa8 16-bit data */
+ .quad 0x0000920000000000 /* 0xb0 16-bit data */
/*
* The APM segments have byte granularity and their bases
diff --git a/drivers/pnp/pnpbios/bioscalls.c b/drivers/pnp/pnpbios/bioscalls.c
index 37bacfc..a721261 100644
--- a/drivers/pnp/pnpbios/bioscalls.c
+++ b/drivers/pnp/pnpbios/bioscalls.c
@@ -283,12 +283,15 @@ int pnp_bios_dev_node_info(struct pnp_dev_node_info *data)
static int __pnp_bios_get_dev_node(u8 *nodenum, char boot, struct pnp_bios_node *data)
{
u16 status;
+ u16 tmp_nodenum;
if (!pnp_bios_present())
return PNP_FUNCTION_NOT_SUPPORTED;
if ( !boot && pnpbios_dont_use_current_config )
return PNP_FUNCTION_NOT_SUPPORTED;
+ tmp_nodenum = *nodenum;
status = call_pnp_bios(PNP_GET_SYS_DEV_NODE, 0, PNP_TS1, 0, PNP_TS2, boot ? 2 : 1, PNP_DS, 0,
- nodenum, sizeof(char), data, 65536);
+ &tmp_nodenum, sizeof(tmp_nodenum), data, 65536);
+ *nodenum = tmp_nodenum;
return status;
}
diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h
index 24cc0c8..9c0593b 100644
--- a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -54,7 +54,7 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
); } while(0)
#define set_base(ldt,base) _set_base( ((char *)&(ldt)) , (base) )
-#define set_limit(ldt,limit) _set_limit( ((char *)&(ldt)) , ((limit)-1)>>12 )
+#define set_limit(ldt,limit) _set_limit( ((char *)&(ldt)) , ((limit)-1) )
/*
* Load a segment. Fall back on loading the zero
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