diff mbox series

[v10,6/8] linux-user/elfload: Move PT_INTERP detection to first loop

Message ID 20201002215955.254866-7-richard.henderson@linaro.org
State Superseded
Headers show
Series linux-user: User support for AArch64 BTI | expand

Commit Message

Richard Henderson Oct. 2, 2020, 9:59 p.m. UTC
For BTI, we need to know if the executable is static or dynamic,
which means looking for PT_INTERP earlier.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 60 +++++++++++++++++++++++---------------------
 1 file changed, 31 insertions(+), 29 deletions(-)

Comments

Philippe Mathieu-Daudé Oct. 3, 2020, 5:38 p.m. UTC | #1
On 10/2/20 11:59 PM, Richard Henderson wrote:
> For BTI, we need to know if the executable is static or dynamic,

> which means looking for PT_INTERP earlier.

> 

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  linux-user/elfload.c | 60 +++++++++++++++++++++++---------------------

>  1 file changed, 31 insertions(+), 29 deletions(-)

> 

> diff --git a/linux-user/elfload.c b/linux-user/elfload.c

> index 735ebfa190..6b422990ff 100644

> --- a/linux-user/elfload.c

> +++ b/linux-user/elfload.c

> @@ -2421,8 +2421,10 @@ static void load_elf_image(const char *image_name, int image_fd,

>  

>      mmap_lock();

>  

> -    /* Find the maximum size of the image and allocate an appropriate

> -       amount of memory to handle that.  */

> +    /*

> +     * Find the maximum size of the image and allocate an appropriate

> +     * amount of memory to handle that.  Locate the interpreter, if any.

> +     */

>      loaddr = -1, hiaddr = 0;

>      info->alignment = 0;

>      for (i = 0; i < ehdr->e_phnum; ++i) {

> @@ -2438,6 +2440,33 @@ static void load_elf_image(const char *image_name, int image_fd,

>              }

>              ++info->nsegs;

>              info->alignment |= eppnt->p_align;

> +        } else if (eppnt->p_type == PT_INTERP && pinterp_name) {

> +            char *interp_name;

> +

> +            if (*pinterp_name) {

> +                errmsg = "Multiple PT_INTERP entries";

> +                goto exit_errmsg;

> +            }

> +            interp_name = malloc(eppnt->p_filesz);

> +            if (!interp_name) {

> +                goto exit_perror;

> +            }

> +

> +            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {

> +                memcpy(interp_name, bprm_buf + eppnt->p_offset,

> +                       eppnt->p_filesz);

> +            } else {

> +                retval = pread(image_fd, interp_name, eppnt->p_filesz,

> +                               eppnt->p_offset);

> +                if (retval != eppnt->p_filesz) {


Preexisting, free(interp_name)?

> +                    goto exit_perror;

> +                }

> +            }

> +            if (interp_name[eppnt->p_filesz - 1] != 0) {

> +                errmsg = "Invalid PT_INTERP entry";


Ditto, otherwise:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>


> +                goto exit_errmsg;

> +            }

> +            *pinterp_name = interp_name;

>          }

>      }

>  

> @@ -2590,33 +2619,6 @@ static void load_elf_image(const char *image_name, int image_fd,

>              if (vaddr_em > info->brk) {

>                  info->brk = vaddr_em;

>              }

> -        } else if (eppnt->p_type == PT_INTERP && pinterp_name) {

> -            char *interp_name;

> -

> -            if (*pinterp_name) {

> -                errmsg = "Multiple PT_INTERP entries";

> -                goto exit_errmsg;

> -            }

> -            interp_name = malloc(eppnt->p_filesz);

> -            if (!interp_name) {

> -                goto exit_perror;

> -            }

> -

> -            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {

> -                memcpy(interp_name, bprm_buf + eppnt->p_offset,

> -                       eppnt->p_filesz);

> -            } else {

> -                retval = pread(image_fd, interp_name, eppnt->p_filesz,

> -                               eppnt->p_offset);

> -                if (retval != eppnt->p_filesz) {

> -                    goto exit_perror;

> -                }

> -            }

> -            if (interp_name[eppnt->p_filesz - 1] != 0) {

> -                errmsg = "Invalid PT_INTERP entry";

> -                goto exit_errmsg;

> -            }

> -            *pinterp_name = interp_name;

>  #ifdef TARGET_MIPS

>          } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) {

>              Mips_elf_abiflags_v0 abiflags;

>
Philippe Mathieu-Daudé Oct. 3, 2020, 6:05 p.m. UTC | #2
On 10/3/20 7:38 PM, Philippe Mathieu-Daudé wrote:
> On 10/2/20 11:59 PM, Richard Henderson wrote:

>> For BTI, we need to know if the executable is static or dynamic,

>> which means looking for PT_INTERP earlier.

>>

>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

>> ---

>>  linux-user/elfload.c | 60 +++++++++++++++++++++++---------------------

>>  1 file changed, 31 insertions(+), 29 deletions(-)

>>

>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c

>> index 735ebfa190..6b422990ff 100644

>> --- a/linux-user/elfload.c

>> +++ b/linux-user/elfload.c

>> @@ -2421,8 +2421,10 @@ static void load_elf_image(const char *image_name, int image_fd,

>>  

>>      mmap_lock();

>>  

>> -    /* Find the maximum size of the image and allocate an appropriate

>> -       amount of memory to handle that.  */

>> +    /*

>> +     * Find the maximum size of the image and allocate an appropriate

>> +     * amount of memory to handle that.  Locate the interpreter, if any.

>> +     */

>>      loaddr = -1, hiaddr = 0;

>>      info->alignment = 0;

>>      for (i = 0; i < ehdr->e_phnum; ++i) {

>> @@ -2438,6 +2440,33 @@ static void load_elf_image(const char *image_name, int image_fd,

>>              }

>>              ++info->nsegs;

>>              info->alignment |= eppnt->p_align;

>> +        } else if (eppnt->p_type == PT_INTERP && pinterp_name) {

>> +            char *interp_name;

>> +

>> +            if (*pinterp_name) {

>> +                errmsg = "Multiple PT_INTERP entries";

>> +                goto exit_errmsg;

>> +            }

>> +            interp_name = malloc(eppnt->p_filesz);

>> +            if (!interp_name) {

>> +                goto exit_perror;

>> +            }

>> +

>> +            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {

>> +                memcpy(interp_name, bprm_buf + eppnt->p_offset,

>> +                       eppnt->p_filesz);

>> +            } else {

>> +                retval = pread(image_fd, interp_name, eppnt->p_filesz,

>> +                               eppnt->p_offset);

>> +                if (retval != eppnt->p_filesz) {

> 

> Preexisting, free(interp_name)?


I just sent a patch using g_steal_pointer() instead:
https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg00792.html
(Maybe I should have tagged it RFC as this is the first
time I try this API).

> 

>> +                    goto exit_perror;

>> +                }

>> +            }

>> +            if (interp_name[eppnt->p_filesz - 1] != 0) {

>> +                errmsg = "Invalid PT_INTERP entry";

> 

> Ditto, otherwise:

> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> 

>> +                goto exit_errmsg;

>> +            }

>> +            *pinterp_name = interp_name;

>>          }

>>      }

>>  

>> @@ -2590,33 +2619,6 @@ static void load_elf_image(const char *image_name, int image_fd,

>>              if (vaddr_em > info->brk) {

>>                  info->brk = vaddr_em;

>>              }

>> -        } else if (eppnt->p_type == PT_INTERP && pinterp_name) {

>> -            char *interp_name;

>> -

>> -            if (*pinterp_name) {

>> -                errmsg = "Multiple PT_INTERP entries";

>> -                goto exit_errmsg;

>> -            }

>> -            interp_name = malloc(eppnt->p_filesz);

>> -            if (!interp_name) {

>> -                goto exit_perror;

>> -            }

>> -

>> -            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {

>> -                memcpy(interp_name, bprm_buf + eppnt->p_offset,

>> -                       eppnt->p_filesz);

>> -            } else {

>> -                retval = pread(image_fd, interp_name, eppnt->p_filesz,

>> -                               eppnt->p_offset);

>> -                if (retval != eppnt->p_filesz) {

>> -                    goto exit_perror;

>> -                }

>> -            }

>> -            if (interp_name[eppnt->p_filesz - 1] != 0) {

>> -                errmsg = "Invalid PT_INTERP entry";

>> -                goto exit_errmsg;

>> -            }

>> -            *pinterp_name = interp_name;

>>  #ifdef TARGET_MIPS

>>          } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) {

>>              Mips_elf_abiflags_v0 abiflags;

>>

> 

>
diff mbox series

Patch

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 735ebfa190..6b422990ff 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2421,8 +2421,10 @@  static void load_elf_image(const char *image_name, int image_fd,
 
     mmap_lock();
 
-    /* Find the maximum size of the image and allocate an appropriate
-       amount of memory to handle that.  */
+    /*
+     * Find the maximum size of the image and allocate an appropriate
+     * amount of memory to handle that.  Locate the interpreter, if any.
+     */
     loaddr = -1, hiaddr = 0;
     info->alignment = 0;
     for (i = 0; i < ehdr->e_phnum; ++i) {
@@ -2438,6 +2440,33 @@  static void load_elf_image(const char *image_name, int image_fd,
             }
             ++info->nsegs;
             info->alignment |= eppnt->p_align;
+        } else if (eppnt->p_type == PT_INTERP && pinterp_name) {
+            char *interp_name;
+
+            if (*pinterp_name) {
+                errmsg = "Multiple PT_INTERP entries";
+                goto exit_errmsg;
+            }
+            interp_name = malloc(eppnt->p_filesz);
+            if (!interp_name) {
+                goto exit_perror;
+            }
+
+            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {
+                memcpy(interp_name, bprm_buf + eppnt->p_offset,
+                       eppnt->p_filesz);
+            } else {
+                retval = pread(image_fd, interp_name, eppnt->p_filesz,
+                               eppnt->p_offset);
+                if (retval != eppnt->p_filesz) {
+                    goto exit_perror;
+                }
+            }
+            if (interp_name[eppnt->p_filesz - 1] != 0) {
+                errmsg = "Invalid PT_INTERP entry";
+                goto exit_errmsg;
+            }
+            *pinterp_name = interp_name;
         }
     }
 
@@ -2590,33 +2619,6 @@  static void load_elf_image(const char *image_name, int image_fd,
             if (vaddr_em > info->brk) {
                 info->brk = vaddr_em;
             }
-        } else if (eppnt->p_type == PT_INTERP && pinterp_name) {
-            char *interp_name;
-
-            if (*pinterp_name) {
-                errmsg = "Multiple PT_INTERP entries";
-                goto exit_errmsg;
-            }
-            interp_name = malloc(eppnt->p_filesz);
-            if (!interp_name) {
-                goto exit_perror;
-            }
-
-            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {
-                memcpy(interp_name, bprm_buf + eppnt->p_offset,
-                       eppnt->p_filesz);
-            } else {
-                retval = pread(image_fd, interp_name, eppnt->p_filesz,
-                               eppnt->p_offset);
-                if (retval != eppnt->p_filesz) {
-                    goto exit_perror;
-                }
-            }
-            if (interp_name[eppnt->p_filesz - 1] != 0) {
-                errmsg = "Invalid PT_INTERP entry";
-                goto exit_errmsg;
-            }
-            *pinterp_name = interp_name;
 #ifdef TARGET_MIPS
         } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) {
             Mips_elf_abiflags_v0 abiflags;