--- name: "aa_change_profile" section: "2" platform: "linux" package: "apparmor" version: "4.1.8-2" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/aa_change_profile" --- # aa\_change\_profile(2) change a tasks profile ## NAME aa\_change\_profile, aa\_change\_onexec - change a tasks profile ## SYNOPSIS **#include \** **int aa\_change\_profile(const char \*profile);** **int aa\_change\_onexec(const char \*profile);** Link with **-lapparmor** when compiling. ## DESCRIPTION An AppArmor profile applies to an executable program; if a portion of the program needs different access permissions than other portions, the program can "change profile" to a different profile. To change into a new profile, it can use the **aa\_change\_profile()** function to do so. It passes in a pointer to the *profile* to transition to. Confined programs wanting to use **aa\_change\_profile()** need to have rules permitting changing to the named profile. See **apparmor.d**(8) for details. If a program wants to return out of the current profile to the original profile, it may use [**aa\_change\_hat**(2)](/aa_change_hat/2.md). Otherwise, the two profiles must have rules permitting changing between the two profiles. Open file descriptors may not be remediated after a call to **aa\_change\_profile()** so the calling program must [**close**(2)](/close/2.md) open file descriptors to ensure they are not available after calling **aa\_change\_profile()**. As **aa\_change\_profile()** is typically used just before [**execve**(2)](/execve/2.md), you may want to use [**open**(2)](/open/2.md) or [**fcntl**(2)](/fcntl/2.md) with close-on-exec. The **aa\_change\_onexec()** function is like the **aa\_change\_profile()** function except it specifies that the profile transition should take place on the next exec instead of immediately. The delayed profile change takes precedence over any exec transition rules within the confining profile. Delaying the profile boundary has a couple of advantages, it removes the need for stub transition profiles and the exec boundary is a natural security layer where potentially sensitive memory is unmapped. ## RETURN VALUE On success zero is returned. On error, -1 is returned, and [**errno**(3)](/errno/3.md) is set appropriately. ## ERRORS - **EINVAL** The apparmor kernel module is not loaded, neither a profile nor a namespace was specified, or the communication via the */proc/\*/attr/current* file did not conform to protocol. - **ENOMEM** Insufficient kernel memory was available. - **EPERM** The calling application is confined by apparmor and the no\_new\_privs bit is set. - **EACCES** The task does not have sufficient permissions to change its domain. - **ENOENT** The specified profile does not exist, or is not visible from the current Namespace. ## EXAMPLE The following example shows a simple, if contrived, use of **aa\_change\_profile()**; a typical use of **aa\_change\_profile()** will **aa\_change\_profile()** just before an [**execve**(2)](/execve/2.md) so that the new child process is permanently confined. ``` #include #include #include #include #include #include #include #include int main(int argc, char * argv[]) { int fd; char buf[10]; char *execve_args[4]; printf("Before aa_change_profile():\n"); if ((fd=open("/etc/passwd", O_RDONLY)) < 0) { perror("Failure opening /etc/passwd"); return 1; } /* Confirm for ourselves that we can really read /etc/passwd */ memset(&buf, 0, 10); if (read(fd, &buf, 10) == -1) { perror("Failure reading /etc/passwd"); return 1; } buf[9] = '\0'; printf("/etc/passwd: %s\n", buf); close(fd); printf("After aa_change_profile():\n"); /* change profile to the "i_cant_be_trusted_anymore" profile, which * should not have read access to /etc/passwd. */ if (aa_change_profile("i_cant_be_trusted_anymore") < 0) { perror("Failure changing profile -- aborting"); _exit(1); } /* confirm that we cannot read /etc/passwd */ execve_args[0] = "/usr/bin/head"; execve_args[1] = "-1"; execve_args[2] = "/etc/passwd"; execve_args[3] = NULL; execve("/usr/bin/head", execve_args, NULL); perror("execve"); _exit(1); } ``` This code example requires a profile similar to the following to be loaded with [**apparmor\_parser**(8)](/apparmor_parser/8.md): ``` profile i_cant_be_trusted_anymore { /etc/ld.so.cache mr, /lib/ld-*.so* mrix, /lib/libc*.so* mr, /usr/bin/head ix, } ``` The output when run: ``` $ /tmp/change_p Before aa_change_profile(): /etc/passwd: root:x:0: After aa_change_profile(): /usr/bin/head: cannot open `/etc/passwd' for reading: Permission denied $ ``` If /tmp/change\_p is to be confined as well, then the following profile can be used (in addition to the one for 'i\_cant\_be\_trusted\_anymore', above): ``` # Confine change_p to be able to read /etc/passwd and aa_change_profile() # to the 'i_cant_be_trusted_anymore' profile. /tmp/change_p { /etc/ld.so.cache mr, /lib/ld-*.so* mrix, /lib/libc*.so* mr, /etc/passwd r, # Needed for aa_change_profile() /usr/lib/libapparmor*.so* mr, /proc/[0-9]*/attr/current w, change_profile -> i_cant_be_trusted_anymore, } ``` ## BUGS None known. If you find any, please report them at \. Note that using [**aa\_change\_profile**(2)](/aa_change_profile/2.md) without [**execve**(2)](/execve/2.md) provides no memory barriers between different areas of a program; if address space separation is required, then separate processes should be used. ## SEE ALSO [**apparmor**(7)](/apparmor/7.md), [**apparmor.d**(5)](/apparmor.d/5.md), [**apparmor\_parser**(8)](/apparmor_parser/8.md), [**aa\_change\_hat**(2)](/aa_change_hat/2.md) and \.