Patchwork linux-user: fix emulation of getdents

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Submitter Dmitry V. Levin
Date Aug. 16, 2012, 9:20 p.m.
Message ID <20120816212019.GB3688@altlinux.org>
Download mbox | patch
Permalink /patch/178099/
State New
Headers show

Comments

Dmitry V. Levin - Aug. 16, 2012, 9:20 p.m.
In case when TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64, the last
byte of the target dirent structure (aka d_type byte) was never copied
from the native dirent structure, thus breaking everything that relies
on valid d_type value, e.g. glob(3).

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
 linux-user/syscall.c      | 7 +++----
 linux-user/syscall_defs.h | 3 ++-
 2 files changed, 5 insertions(+), 5 deletions(-)
陳韋任 - Aug. 17, 2012, 7:33 a.m.
CC'ed to linux-user maintainer, Riku.

On Fri, Aug 17, 2012 at 01:20:19AM +0400, Dmitry V. Levin wrote:
> In case when TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64, the last
> byte of the target dirent structure (aka d_type byte) was never copied
> from the native dirent structure, thus breaking everything that relies
> on valid d_type value, e.g. glob(3).
> 
> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> ---
>  linux-user/syscall.c      | 7 +++----
>  linux-user/syscall_defs.h | 3 ++-
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 41c869b..2b6025b 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7030,10 +7030,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>                      tde->d_ino = tswapal(de->d_ino);
>                      tde->d_off = tswapal(de->d_off);
>  		    tnamelen = treclen - (2 * sizeof(abi_long) + 2);
> -		    if (tnamelen > 256)
> -                        tnamelen = 256;
> -                    /* XXX: may not be correct */
> -                    pstrcpy(tde->d_name, tnamelen, de->d_name);
> +		    if (tnamelen > sizeof(tde->d_name))
> +                        tnamelen = sizeof(tde->d_name);
> +                    memcpy(tde->d_name, de->d_name, tnamelen);
>                      de = (struct linux_dirent *)((char *)de + reclen);
>                      len -= reclen;
>                      tde = (struct target_dirent *)((char *)tde + treclen);
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 2cfda5a..f27a8d4 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -258,7 +258,8 @@ struct target_dirent {
>  	abi_long	d_ino;
>  	abi_long	d_off;
>  	unsigned short	d_reclen;
> -	char		d_name[256]; /* We must not include limits.h! */
> +	char		d_name[257]; 	/* We must not include limits.h! */
> +					/* 257 = NAME_MAX + '\0' + d_type */
>  };
>  
>  struct target_dirent64 {
> 
> -- 
> ldv
Blue Swirl - Aug. 18, 2012, 2:20 p.m.
On Thu, Aug 16, 2012 at 9:20 PM, Dmitry V. Levin <ldv@altlinux.org> wrote:
> In case when TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64, the last
> byte of the target dirent structure (aka d_type byte) was never copied
> from the native dirent structure, thus breaking everything that relies
> on valid d_type value, e.g. glob(3).
>
> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> ---
>  linux-user/syscall.c      | 7 +++----
>  linux-user/syscall_defs.h | 3 ++-
>  2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 41c869b..2b6025b 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7030,10 +7030,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>                      tde->d_ino = tswapal(de->d_ino);
>                      tde->d_off = tswapal(de->d_off);
>                     tnamelen = treclen - (2 * sizeof(abi_long) + 2);
> -                   if (tnamelen > 256)
> -                        tnamelen = 256;
> -                    /* XXX: may not be correct */
> -                    pstrcpy(tde->d_name, tnamelen, de->d_name);
> +                   if (tnamelen > sizeof(tde->d_name))
> +                        tnamelen = sizeof(tde->d_name);

Missing braces, please read CODING_STYLE.

Otherwise patch looks good.

> +                    memcpy(tde->d_name, de->d_name, tnamelen);
>                      de = (struct linux_dirent *)((char *)de + reclen);
>                      len -= reclen;
>                      tde = (struct target_dirent *)((char *)tde + treclen);
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 2cfda5a..f27a8d4 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -258,7 +258,8 @@ struct target_dirent {
>         abi_long        d_ino;
>         abi_long        d_off;
>         unsigned short  d_reclen;
> -       char            d_name[256]; /* We must not include limits.h! */
> +       char            d_name[257];    /* We must not include limits.h! */
> +                                       /* 257 = NAME_MAX + '\0' + d_type */
>  };
>
>  struct target_dirent64 {
>
> --
> ldv
>

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 41c869b..2b6025b 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7030,10 +7030,9 @@  abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                     tde->d_ino = tswapal(de->d_ino);
                     tde->d_off = tswapal(de->d_off);
 		    tnamelen = treclen - (2 * sizeof(abi_long) + 2);
-		    if (tnamelen > 256)
-                        tnamelen = 256;
-                    /* XXX: may not be correct */
-                    pstrcpy(tde->d_name, tnamelen, de->d_name);
+		    if (tnamelen > sizeof(tde->d_name))
+                        tnamelen = sizeof(tde->d_name);
+                    memcpy(tde->d_name, de->d_name, tnamelen);
                     de = (struct linux_dirent *)((char *)de + reclen);
                     len -= reclen;
                     tde = (struct target_dirent *)((char *)tde + treclen);
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 2cfda5a..f27a8d4 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -258,7 +258,8 @@  struct target_dirent {
 	abi_long	d_ino;
 	abi_long	d_off;
 	unsigned short	d_reclen;
-	char		d_name[256]; /* We must not include limits.h! */
+	char		d_name[257]; 	/* We must not include limits.h! */
+					/* 257 = NAME_MAX + '\0' + d_type */
 };
 
 struct target_dirent64 {